Seeded X-ray free-electron laser generating radiation with laser statistical properties

<!DOCTYPE html> <html lang="en" class="grade-c"> <head> <title>Seeded X-ray free-electron laser generating radiation with laser statistical properties | Nature Communications</title> <link rel="alternate" type="application/rss+xml" href="https://www.nature.com/ncomms.rss"/> <script id="save-data-connection-testing"> function hasConnection() { return navigator.connection || navigator.mozConnection || navigator.webkitConnection || navigator.msConnection; } function createLink(src) { var preloadLink = document.createElement("link"); preloadLink.rel = "preload"; preloadLink.href = src; preloadLink.as = "font"; preloadLink.type = "font/woff2"; preloadLink.crossOrigin = ""; document.head.insertBefore(preloadLink, document.head.firstChild); } var connectionDetail = { saveDataEnabled: false, slowConnection: false }; var connection = hasConnection(); if (connection) { connectionDetail.saveDataEnabled = connection.saveData; if (/\slow-2g|2g/.test(connection.effectiveType)) { connectionDetail.slowConnection = true; } } if (!(connectionDetail.saveDataEnabled || connectionDetail.slowConnection)) { createLink("/static/fonts/HardingText-Regular-Web-cecd90984f.woff2"); } else { document.documentElement.classList.add('save-data'); } </script> <link rel="preconnect" href="https://cmp.nature.com" crossorigin> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="applicable-device" content="pc,mobile"> <meta name="viewport" content="width=device-width,initial-scale=1.0,maximum-scale=5,user-scalable=yes"> <meta name="360-site-verification" content="5a2dc4ab3fcb9b0393241ffbbb490480" /> <script data-test="dataLayer"> window.dataLayer = [{"content":{"category":{"contentType":"article","legacy":{"webtrendsPrimaryArticleType":"research","webtrendsSubjectTerms":"free-electron-lasers;spectroscopy","webtrendsContentCategory":null,"webtrendsContentCollection":"Free-Electron Lasers","webtrendsContentGroup":"Nature Communications","webtrendsContentGroupType":null,"webtrendsContentSubGroup":"Article","status":null}},"article":{"doi":"10.1038/s41467-018-06743-8"},"attributes":{"cms":null,"deliveryPlatform":"oscar","copyright":{"open":true,"legacy":{"webtrendsLicenceType":"http://creativecommons.org/licenses/by/4.0/"}}},"contentInfo":{"authors":["Oleg Yu. Gorobtsov","Giuseppe Mercurio","Flavio Capotondi","Petr Skopintsev","Sergey Lazarev","Ivan A. Zaluzhnyy","Miltcho B. Danailov","Martina Dell’Angela","Michele Manfredda","Emanuele Pedersoli","Luca Giannessi","Maya Kiskinova","Kevin C. Prince","Wilfried Wurth","Ivan A. Vartanyants"],"publishedAt":1540771200,"publishedAtString":"2018-10-29","title":"Seeded X-ray free-electron laser generating radiation with laser statistical properties","legacy":null,"publishedAtTime":null,"documentType":"aplusplus","subjects":"Free-electron lasers,Optical spectroscopy"},"journal":{"pcode":"ncomms","title":"nature communications","volume":"9","issue":"1","id":41467,"publishingModel":"Open Access"},"authorization":{"status":true},"features":[{"name":"furtherReadingSection","present":true}],"collection":{"id":"cssxtbybyl"}},"page":{"category":{"pageType":"article"},"attributes":{"template":"mosaic","featureFlags":[{"name":"nature-onwards-journey","active":false}],"testGroup":null},"search":null},"privacy":{},"version":"1.0.0","product":null,"session":null,"user":null,"backHalfContent":true,"country":"SG","hasBody":true,"uneditedManuscript":false,"twitterId":["o3xnx","o43y9","o3ef7"],"baiduId":"d38bce82bcb44717ccc29a90c4b781ea","japan":false}]; window.dataLayer.push({ ga4MeasurementId: 'G-ERRNTNZ807', ga360TrackingId: 'UA-71668177-1', twitterId: ['3xnx', 'o43y9', 'o3ef7'], baiduId: 'd38bce82bcb44717ccc29a90c4b781ea', ga4ServerUrl: 'https://collect.nature.com', imprint: 'nature' }); </script> <script> (function(w, d) { w.config = w.config || {}; w.config.mustardcut = false; if (w.matchMedia && w.matchMedia('only print, only all and (prefers-color-scheme: no-preference), only all and (prefers-color-scheme: light), only all and (prefers-color-scheme: dark)').matches) { w.config.mustardcut = true; d.classList.add('js'); d.classList.remove('grade-c'); d.classList.remove('no-js'); } })(window, document.documentElement); </script> <style>@media only print, only all and (prefers-color-scheme: no-preference), only all and (prefers-color-scheme: light), only all and (prefers-color-scheme: dark) { .c-article-editorial-summary__container .c-article-editorial-summary__article-title,.c-card--major .c-card__title,.c-card__title,.u-h2,.u-h3,h2,h3{-webkit-font-smoothing:antialiased;font-family:Harding,Palatino,serif;font-weight:700;letter-spacing:-.0117156rem}.c-article-editorial-summary__container .c-article-editorial-summary__article-title,.c-card__title,.u-h3,h3{font-size:1.25rem;line-height:1.4rem}.c-reading-companion__figure-title,.u-h4,h4{-webkit-font-smoothing:antialiased;font-weight:700;line-height:1.4rem}html{text-size-adjust:100%;box-sizing:border-box;font-size:100%;height:100%;line-height:1.15;overflow-y:scroll}body{background:#eee;color:#222;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:1.125rem;line-height:1.76;margin:0;min-height:100%}details,main{display:block}h1{font-size:2em;margin:.67em 0}a,sup{vertical-align:baseline}a{background-color:transparent;color:#069;overflow-wrap:break-word;text-decoration:underline;text-decoration-skip-ink:auto;word-break:break-word}b{font-weight:bolder}sup{font-size:75%;line-height:0;position:relative;top:-.5em}img{border:0;height:auto;max-width:100%;vertical-align:middle}button,input,select{font-family:inherit;font-size:100%;line-height:1.15;margin:0}button,input{overflow:visible}button,select{text-transform:none}[type=submit],button{-webkit-appearance:button}[type=checkbox]{box-sizing:border-box;padding:0}summary{display:list-item}[hidden]{display:none}button{border-radius:0;cursor:pointer;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif}h1{-webkit-font-smoothing:antialiased;font-family:Harding,Palatino,serif;font-size:2rem;font-weight:700;letter-spacing:-.0390625rem;line-height:2.25rem}.c-card--major .c-card__title,.u-h2,.u-h3,h2{font-family:Harding,Palatino,serif;letter-spacing:-.0117156rem}.c-card--major .c-card__title,.u-h2,h2{-webkit-font-smoothing:antialiased;font-size:1.5rem;font-weight:700;line-height:1.6rem}.u-h3{font-size:1.25rem}.c-card__title,.c-reading-companion__figure-title,.u-h3,.u-h4,h4,h5,h6{-webkit-font-smoothing:antialiased;font-weight:700;line-height:1.4rem}.c-article-editorial-summary__container .c-article-editorial-summary__article-title,.c-card__title,h3{font-family:Harding,Palatino,serif;font-size:1.25rem}.c-article-editorial-summary__container .c-article-editorial-summary__article-title,h3{-webkit-font-smoothing:antialiased;font-weight:700;letter-spacing:-.0117156rem;line-height:1.4rem}.c-reading-companion__figure-title,.u-h4,h4{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:1.125rem;letter-spacing:-.0117156rem}button:focus{outline:3px solid #fece3e;will-change:transform}input+label{padding-left:.5em}nav ol,nav ul{list-style:none none}p:empty{display:none}.sans-serif{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif}.article-page{background:#fff}.c-article-header{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;margin-bottom:40px}.c-article-identifiers{color:#6f6f6f;display:flex;flex-wrap:wrap;font-size:1rem;line-height:1.3;list-style:none;margin:0 0 8px;padding:0}.c-article-identifiers__item{border-right:1px solid #6f6f6f;list-style:none;margin-right:8px;padding-right:8px}.c-article-identifiers__item:last-child{border-right:0;margin-right:0;padding-right:0}.c-article-title{font-size:1.5rem;line-height:1.25;margin:0 0 16px}@media only screen and (min-width:768px){.c-article-title{font-size:1.875rem;line-height:1.2}}.c-article-author-list{display:inline;font-size:1rem;list-style:none;margin:0 8px 0 0;padding:0;width:100%}.c-article-author-list__item{display:inline;padding-right:0}.c-article-author-list svg{margin-left:4px}.c-article-author-list__show-more{display:none;margin-right:4px}.c-article-author-list__button,.js .c-article-author-list__item--hide,.js .c-article-author-list__show-more{display:none}.js .c-article-author-list--long .c-article-author-list__show-more,.js .c-article-author-list--long+.c-article-author-list__button{display:inline}@media only screen and (max-width:539px){.js .c-article-author-list__item--hide-small-screen{display:none}.js .c-article-author-list--short .c-article-author-list__show-more,.js .c-article-author-list--short+.c-article-author-list__button{display:inline}}#uptodate-client,.js .c-article-author-list--expanded .c-article-author-list__show-more{display:none!important}.js .c-article-author-list--expanded .c-article-author-list__item--hide-small-screen{display:inline!important}.c-article-author-list__button,.c-button-author-list{background:#ebf1f5;border:4px solid #ebf1f5;border-radius:20px;color:#666;font-size:.875rem;line-height:1.4;padding:2px 11px 2px 8px;text-decoration:none}.c-article-author-list__button svg,.c-button-author-list svg{margin:1px 4px 0 0}.c-article-author-list__button:hover,.c-button-author-list:hover{background:#069;border-color:transparent;color:#fff}.c-article-info-details{font-size:1rem;margin-bottom:8px;margin-top:16px}.c-article-info-details__cite-as{border-left:1px solid #6f6f6f;margin-left:8px;padding-left:8px}.c-article-metrics-bar{display:flex;flex-wrap:wrap;font-size:1rem;line-height:1.3}.c-article-metrics-bar__wrapper{margin:16px 0}.c-article-metrics-bar__item{align-items:baseline;border-right:1px solid #6f6f6f;margin-right:8px}.c-article-metrics-bar__item:last-child{border-right:0}.c-article-metrics-bar__count{font-weight:700;margin:0}.c-article-metrics-bar__label{color:#626262;font-style:normal;font-weight:400;margin:0 10px 0 5px}.c-article-metrics-bar__details{margin:0}.c-article-main-column{font-family:Harding,Palatino,serif;margin-right:8.6%;width:60.2%}@media only screen and (max-width:1023px){.c-article-main-column{margin-right:0;width:100%}}.c-article-extras{float:left;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;width:31.2%}@media only screen and (max-width:1023px){.c-article-extras{display:none}}.c-article-associated-content__container .c-article-associated-content__title,.c-article-section__title{border-bottom:2px solid #d5d5d5;font-size:1.25rem;margin:0;padding-bottom:8px}@media only screen and (min-width:768px){.c-article-associated-content__container .c-article-associated-content__title,.c-article-section__title{font-size:1.5rem;line-height:1.24}}.c-article-associated-content__container .c-article-associated-content__title{margin-bottom:8px}.c-article-body p{margin-bottom:24px;margin-top:0}.c-article-section{clear:both}.c-article-section__content{margin-bottom:40px;padding-top:8px}@media only screen and (max-width:1023px){.c-article-section__content{padding-left:0}}.c-article-authors-search{margin-bottom:24px;margin-top:0}.c-article-authors-search__item,.c-article-authors-search__title{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif}.c-article-authors-search__title{color:#626262;font-size:1.05rem;font-weight:700;margin:0;padding:0}.c-article-authors-search__item{font-size:1rem}.c-article-authors-search__text{margin:0}.c-article-license__badge,c-card__section{margin-top:8px}.c-code-block{border:1px solid #eee;font-family:monospace;margin:0 0 24px;padding:20px}.c-code-block__heading{font-weight:400;margin-bottom:16px}.c-code-block__line{display:block;overflow-wrap:break-word;white-space:pre-wrap}.c-article-share-box__no-sharelink-info{font-size:.813rem;font-weight:700;margin-bottom:24px;padding-top:4px}.c-article-share-box__only-read-input{border:1px solid #d5d5d5;box-sizing:content-box;display:inline-block;font-size:.875rem;font-weight:700;height:24px;margin-bottom:8px;padding:8px 10px}.c-article-share-box__button--link-like{background-color:transparent;border:0;color:#069;cursor:pointer;font-size:.875rem;margin-bottom:8px;margin-left:10px}.c-article-editorial-summary__container{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:1rem}.c-article-editorial-summary__container .c-article-editorial-summary__content p:last-child{margin-bottom:0}.c-article-editorial-summary__container .c-article-editorial-summary__content--less{max-height:9.5rem;overflow:hidden}.c-article-editorial-summary__container .c-article-editorial-summary__button{background-color:#fff;border:0;color:#069;font-size:.875rem;margin-bottom:16px}.c-article-editorial-summary__container .c-article-editorial-summary__button.active,.c-article-editorial-summary__container .c-article-editorial-summary__button.hover,.c-article-editorial-summary__container .c-article-editorial-summary__button:active,.c-article-editorial-summary__container .c-article-editorial-summary__button:hover{text-decoration:underline;text-decoration-skip-ink:auto}.c-article-associated-content__container .c-article-associated-content__collection-label{font-size:.875rem;line-height:1.4}.c-article-associated-content__container .c-article-associated-content__collection-title{line-height:1.3}.c-context-bar{box-shadow:0 0 10px 0 rgba(51,51,51,.2);position:relative;width:100%}.c-context-bar__title{display:none}.c-reading-companion{clear:both;min-height:389px}.c-reading-companion__sticky{max-width:389px}.c-reading-companion__scroll-pane{margin:0;min-height:200px;overflow:hidden auto}.c-reading-companion__tabs{display:flex;flex-flow:row nowrap;font-size:1rem;list-style:none;margin:0 0 8px;padding:0}.c-reading-companion__tabs>li{flex-grow:1}.c-reading-companion__tab{background-color:#eee;border:1px solid #d5d5d5;border-image:initial;border-left-width:0;color:#069;font-size:1rem;padding:8px 8px 8px 15px;text-align:left;width:100%}.c-reading-companion__tabs li:first-child .c-reading-companion__tab{border-left-width:1px}.c-reading-companion__tab--active{background-color:#fff;border-bottom:1px solid #fff;color:#222;font-weight:700}.c-reading-companion__sections-list{list-style:none;padding:0}.c-reading-companion__figures-list,.c-reading-companion__references-list{list-style:none;min-height:389px;padding:0}.c-reading-companion__references-list--numeric{list-style:decimal inside}.c-reading-companion__sections-list{margin:0 0 8px;min-height:50px}.c-reading-companion__section-item{font-size:1rem;padding:0}.c-reading-companion__section-item a{display:block;line-height:1.5;overflow:hidden;padding:8px 0 8px 16px;text-overflow:ellipsis;white-space:nowrap}.c-reading-companion__figure-item{border-top:1px solid #d5d5d5;font-size:1rem;padding:16px 8px 16px 0}.c-reading-companion__figure-item:first-child{border-top:none;padding-top:8px}.c-reading-companion__reference-item{border-top:1px solid #d5d5d5;font-size:1rem;padding:8px 8px 8px 16px}.c-reading-companion__reference-item:first-child{border-top:none}.c-reading-companion__reference-item a{word-break:break-word}.c-reading-companion__reference-citation{display:inline}.c-reading-companion__reference-links{font-size:.813rem;font-weight:700;list-style:none;margin:8px 0 0;padding:0;text-align:right}.c-reading-companion__reference-links>a{display:inline-block;padding-left:8px}.c-reading-companion__reference-links>a:first-child{display:inline-block;padding-left:0}.c-reading-companion__figure-title{display:block;margin:0 0 8px}.c-reading-companion__figure-links{display:flex;justify-content:space-between;margin:8px 0 0}.c-reading-companion__figure-links>a{align-items:center;display:flex}.c-reading-companion__figure-full-link svg{height:.8em;margin-left:2px}.c-reading-companion__panel{border-top:none;display:none;margin-top:0;padding-top:0}.c-cod,.c-reading-companion__panel--active{display:block}.c-cod{font-size:1rem;width:100%}.c-cod__form{background:#ebf0f3}.c-cod__prompt{font-size:1.125rem;line-height:1.3;margin:0 0 24px}.c-cod__label{display:block;margin:0 0 4px}.c-cod__row{display:flex;margin:0 0 16px}.c-cod__row:last-child{margin:0}.c-cod__input{border:1px solid #d5d5d5;border-radius:2px;flex-basis:75%;flex-shrink:0;margin:0;padding:13px}.c-cod__input--submit{background-color:#069;border:1px solid #069;color:#fff;flex-shrink:1;margin-left:8px;transition:background-color .2s ease-out 0s,color .2s ease-out 0s}.c-cod__input--submit-single{flex-basis:100%;flex-shrink:0;margin:0}.c-cod__input--submit:focus,.c-cod__input--submit:hover{background-color:#fff;color:#069}.c-pdf-download__link .u-icon{padding-top:2px}.c-pdf-download{display:flex;margin-bottom:16px;max-height:48px}@media only screen and (min-width:540px){.c-pdf-download{max-height:none}}@media only screen and (min-width:1024px){.c-pdf-download{max-height:48px}}.c-pdf-download__link{display:flex;flex:1 1 0%}.c-pdf-download__link:hover{text-decoration:none}.c-pdf-download__text{padding-right:4px}@media only screen and (max-width:539px){.c-pdf-download__text{text-transform:capitalize}}@media only screen and (min-width:540px){.c-pdf-download__text{padding-right:8px}}.c-context-bar--sticky .c-pdf-download{display:block;margin-bottom:0;white-space:nowrap}@media only screen and (max-width:539px){.c-pdf-download .u-sticky-visually-hidden{clip:rect(0,0,0,0);border:0;height:1px;margin:-100%;overflow:hidden;padding:0;position:absolute!important;width:1px}}.c-pdf-container{display:flex;justify-content:flex-end}@media only screen and (max-width:539px){.c-pdf-container .c-pdf-download{display:flex;flex-basis:100%}}.c-pdf-container .c-pdf-download+.c-pdf-download{margin-left:16px}.c-article-extras .c-pdf-container .c-pdf-download{width:100%}.c-article-extras .c-pdf-container .c-pdf-download+.c-pdf-download{margin-left:0}@media only screen and (min-width:540px){.c-context-bar--sticky .c-pdf-download__link{align-items:center;flex:1 1 183px}}@media only screen and (max-width:320px){.c-context-bar--sticky .c-pdf-download__link{padding:16px}}.article-page--commercial .c-article-main-column .c-pdf-button__container .c-pdf-download{display:none}@media only screen and (max-width:1023px){.article-page--commercial .c-article-main-column .c-pdf-button__container .c-pdf-download{display:block}}.c-status-message--success{border-bottom:2px solid #00b8b0;justify-content:center;margin-bottom:16px;padding-bottom:8px}.c-recommendations-list__item .c-card{flex-basis:100%}.c-recommendations-list__item .c-card__image{align-items:baseline;flex:1 1 40%;margin:0 0 0 16px;max-width:150px}.c-recommendations-list__item .c-card__image img{border:1px solid #cedbe0;height:auto;min-height:0;position:static}@media only screen and (max-width:1023px){.c-recommendations-list__item .c-card__image{display:none}}.c-card__layout{display:flex;flex:1 1 auto;justify-content:space-between}.c-card__title-recommendation{-webkit-box-orient:vertical;-webkit-line-clamp:4;display:-webkit-box;font-size:1rem;font-weight:700;line-height:1.4;margin:0 0 8px;max-height:5.6em;overflow:hidden!important;text-overflow:ellipsis}.c-card__title-recommendation .c-card__link{color:inherit}.c-card__title-recommendation .c-card__link:hover{text-decoration:underline}.c-card__title-recommendation .MathJax_Display{display:inline!important}.c-card__link:not(.c-card__link--no-block-link):before{z-index:1}.c-article-metrics__heading a,.c-article-metrics__posts .c-card__title a,.c-article-recommendations-card__link{color:inherit}.c-recommendations-column-switch .c-meta{margin-top:auto}.c-article-recommendations-card__meta-type,.c-meta .c-meta__item:first-child{font-weight:700}.c-article-body .c-article-recommendations-card__authors{display:none;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:.875rem;line-height:1.5;margin:0 0 8px}@media only screen and (max-width:539px){.c-article-body .c-article-recommendations-card__authors{display:block;margin:0}}.c-article-metrics__posts .c-card__title{font-size:1.05rem}.c-article-metrics__posts .c-card__title+span{color:#6f6f6f;font-size:1rem}p{overflow-wrap:break-word;word-break:break-word}.c-ad{text-align:center}@media only screen and (min-width:320px){.c-ad{padding:8px}}.c-ad--728x90{background-color:#ccc;display:none}.c-ad--728x90 .c-ad__inner{min-height:calc(1.5em + 94px)}@media only screen and (min-width:768px){.js .c-ad--728x90{display:none}}.c-ad__label{color:#333;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:.875rem;font-weight:400;line-height:1.5;margin-bottom:4px}.c-author-list{color:#6f6f6f;font-family:inherit;font-size:1rem;line-height:inherit;list-style:none;margin:0;padding:0}.c-author-list>li,.c-breadcrumbs>li,.c-footer__links>li,.js .c-author-list,.u-list-comma-separated>li,.u-list-inline>li{display:inline}.c-author-list>li:not(:first-child):not(:last-child):before{content:", "}.c-author-list>li:not(:only-child):last-child:before{content:" & "}.c-author-list--compact{font-size:.875rem;line-height:1.4}.c-author-list--truncated>li:not(:only-child):last-child:before{content:" ... "}.js .c-author-list__hide{display:none;visibility:hidden}.js .c-author-list__hide:first-child+*{margin-block-start:0}.c-meta{color:inherit;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:.875rem;line-height:1.4;list-style:none;margin:0;padding:0}.c-meta--large{font-size:1rem}.c-meta--large .c-meta__item{margin-bottom:8px}.c-meta__item{display:inline-block;margin-bottom:4px}.c-meta__item:not(:last-child){border-right:1px solid #d5d5d5;margin-right:4px;padding-right:4px}@media only screen and (max-width:539px){.c-meta__item--block-sm-max{display:block}.c-meta__item--block-sm-max:not(:last-child){border-right:none;margin-right:0;padding-right:0}}@media only screen and (min-width:1024px){.c-meta__item--block-at-lg{display:block}.c-meta__item--block-at-lg:not(:last-child){border-right:none;margin-right:0;padding-right:0}}.c-meta__type{font-weight:700;text-transform:none}.c-skip-link{background:#069;bottom:auto;color:#fff;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:.875rem;padding:8px;position:absolute;text-align:center;transform:translateY(-100%);z-index:9999}@media (prefers-reduced-motion:reduce){.c-skip-link{transition:top .3s ease-in-out 0s}}@media print{.c-skip-link{display:none}}.c-skip-link:link{color:#fff}.c-status-message{align-items:center;box-sizing:border-box;display:flex;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:1rem;position:relative;width:100%}.c-card__summary>p:last-child,.c-status-message :last-child{margin-bottom:0}.c-status-message--boxed{background-color:#fff;border:1px solid #eee;border-radius:2px;line-height:1.4;padding:16px}.c-status-message__heading{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:1rem;font-weight:700}.c-status-message__icon{fill:currentcolor;display:inline-block;flex:0 0 auto;height:1.5em;margin-right:8px;transform:translate(0);vertical-align:text-top;width:1.5em}.c-status-message__icon--top{align-self:flex-start}.c-status-message--info .c-status-message__icon{color:#003f8d}.c-status-message--boxed.c-status-message--info{border-bottom:4px solid #003f8d}.c-status-message--error .c-status-message__icon{color:#c40606}.c-status-message--boxed.c-status-message--error{border-bottom:4px solid #c40606}.c-status-message--success .c-status-message__icon{color:#00b8b0}.c-status-message--boxed.c-status-message--success{border-bottom:4px solid #00b8b0}.c-status-message--warning .c-status-message__icon{color:#edbc53}.c-status-message--boxed.c-status-message--warning{border-bottom:4px solid #edbc53}.c-breadcrumbs{color:#000;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:1rem;list-style:none;margin:0;padding:0}.c-breadcrumbs__link{color:#666}svg.c-breadcrumbs__chevron{fill:#888;height:10px;margin:4px 4px 0;width:10px}@media only screen and (max-width:539px){.c-breadcrumbs .c-breadcrumbs__item{display:none}.c-breadcrumbs .c-breadcrumbs__item:last-child,.c-breadcrumbs .c-breadcrumbs__item:nth-last-child(2){display:inline}}.c-card{background-color:transparent;border:0;box-shadow:none;display:flex;flex-direction:column;font-size:14px;min-width:0;overflow:hidden;padding:0;position:relative}.c-card--no-shape{background:0 0;border:0;box-shadow:none}.c-card__image{display:flex;justify-content:center;overflow:hidden;padding-bottom:56.25%;position:relative}@supports (aspect-ratio:1/1){.c-card__image{padding-bottom:0}}.c-card__image img{left:0;min-height:100%;min-width:100%;position:absolute}@supports ((-o-object-fit:cover) or (object-fit:cover)){.c-card__image img{height:100%;object-fit:cover;width:100%}}.c-card__body{flex:1 1 auto;padding:16px}.c-card--no-shape .c-card__body{padding:0}.c-card--no-shape .c-card__body:not(:first-child){padding-top:16px}.c-card__title{letter-spacing:-.01875rem;margin-bottom:8px;margin-top:0}[lang=de] .c-card__title{hyphens:auto}.c-card__summary{line-height:1.4}.c-card__summary>p{margin-bottom:5px}.c-card__summary a{text-decoration:underline}.c-card__link:not(.c-card__link--no-block-link):before{bottom:0;content:"";left:0;position:absolute;right:0;top:0}.c-card--flush .c-card__body{padding:0}.c-card--major{font-size:1rem}.c-card--dark{background-color:#29303c;border-width:0;color:#e3e4e5}.c-card--dark .c-card__title{color:#fff}.c-card--dark .c-card__link,.c-card--dark .c-card__summary a{color:inherit}.c-header{background-color:#fff;border-bottom:5px solid #000;font-size:1rem;line-height:1.4;margin-bottom:16px}.c-header__row{padding:0;position:relative}.c-header__row:not(:last-child){border-bottom:1px solid #eee}.c-header__split{align-items:center;display:flex;justify-content:space-between}.c-header__logo-container{flex:1 1 0px;line-height:0;margin:8px 24px 8px 0}.c-header__logo{transform:translateZ(0)}.c-header__logo img{max-height:32px}.c-header__container{margin:0 auto;max-width:1280px}.c-header__menu{align-items:center;display:flex;flex:0 1 auto;flex-wrap:wrap;font-weight:700;gap:8px 8px;line-height:1.4;list-style:none;margin:0 -8px;padding:0}@media print{.c-header__menu{display:none}}@media only screen and (max-width:1023px){.c-header__menu--hide-lg-max{display:none;visibility:hidden}}.c-header__menu--global{font-weight:400;justify-content:flex-end}.c-header__menu--global svg{display:none;visibility:hidden}.c-header__menu--global svg:first-child+*{margin-block-start:0}@media only screen and (min-width:540px){.c-header__menu--global svg{display:block;visibility:visible}}.c-header__menu--journal{font-size:.875rem;margin:8px 0 8px -8px}@media only screen and (min-width:540px){.c-header__menu--journal{flex-wrap:nowrap;font-size:1rem}}.c-header__item{padding-bottom:0;padding-top:0;position:static}.c-header__item--pipe{border-left:2px solid #eee;padding-left:8px}.c-header__item--padding{padding-bottom:8px;padding-top:8px}@media only screen and (min-width:540px){.c-header__item--dropdown-menu{position:relative}}@media only screen and (min-width:1024px){.c-header__item--hide-lg{display:none;visibility:hidden}}@media only screen and (max-width:767px){.c-header__item--hide-md-max{display:none;visibility:hidden}.c-header__item--hide-md-max:first-child+*{margin-block-start:0}}.c-header__link{align-items:center;color:inherit;display:inline-flex;gap:4px 4px;padding:8px;white-space:nowrap}.c-header__link svg{transition-duration:.2s}.c-header__show-text{display:none;visibility:hidden}.has-tethered .c-header__heading--js-hide:first-child+*{margin-block-start:0}@media only screen and (min-width:540px){.c-header__show-text{display:inline;visibility:visible}}.c-header__dropdown{background-color:#000;border-bottom:1px solid #2f2f2f;color:#eee;font-size:.875rem;line-height:1.2;padding:16px 0}@media print{.c-header__dropdown{display:none}}.c-header__heading{display:inline-block;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:1.25rem;font-weight:400;line-height:1.4;margin-bottom:8px}.c-header__heading--keyline{border-top:1px solid;border-color:#2f2f2f;margin-top:16px;padding-top:16px;width:100%}.c-header__list{display:flex;flex-wrap:wrap;gap:0 16px;list-style:none;margin:0 -8px}.c-header__flush{margin:0 -8px}.c-header__visually-hidden{clip:rect(0,0,0,0);border:0;height:1px;margin:-100%;overflow:hidden;padding:0;position:absolute!important;width:1px}.c-header__search-form{margin-bottom:8px}.c-header__search-layout{display:flex;flex-wrap:wrap;gap:16px 16px}.c-header__search-layout>:first-child{flex:999 1 auto}.c-header__search-layout>*{flex:1 1 auto}.c-header__search-layout--max-width{max-width:720px}.c-header__search-button{align-items:center;background-color:transparent;background-image:none;border:1px solid #fff;border-radius:2px;color:#fff;cursor:pointer;display:flex;font-family:sans-serif;font-size:1rem;justify-content:center;line-height:1.15;margin:0;padding:8px 16px;position:relative;text-decoration:none;transition:all .25s ease 0s,color .25s ease 0s,border-color .25s ease 0s;width:100%}.u-button svg,.u-button--primary svg{fill:currentcolor}.c-header__input,.c-header__select{border:1px solid;border-radius:3px;box-sizing:border-box;font-size:1rem;padding:8px 16px;width:100%}.c-header__select{-webkit-appearance:none;background-image:url("data:image/svg+xml,%3Csvg height='16' viewBox='0 0 16 16' width='16' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='m5.58578644 3-3.29289322-3.29289322c-.39052429-.39052429-.39052429-1.02368927 0-1.41421356s1.02368927-.39052429 1.41421356 0l4 4c.39052429.39052429.39052429 1.02368927 0 1.41421356l-4 4c-.39052429.39052429-1.02368927.39052429-1.41421356 0s-.39052429-1.02368927 0-1.41421356z' fill='%23333' fill-rule='evenodd' transform='matrix(0 1 -1 0 11 3)'/%3E%3C/svg%3E");background-position:right .7em top 50%;background-repeat:no-repeat;background-size:1em;box-shadow:0 1px 0 1px rgba(0,0,0,.04);display:block;margin:0;max-width:100%;min-width:150px}@media only screen and (min-width:540px){.c-header__menu--journal .c-header__item--dropdown-menu:last-child .c-header__dropdown.has-tethered{left:auto;right:0}}@media only screen and (min-width:768px){.c-header__menu--journal .c-header__item--dropdown-menu:last-child .c-header__dropdown.has-tethered{left:0;right:auto}}.c-header__dropdown.has-tethered{border-bottom:0;border-radius:0 0 2px 2px;left:0;position:absolute;top:100%;transform:translateY(5px);width:100%;z-index:1}@media only screen and (min-width:540px){.c-header__dropdown.has-tethered{transform:translateY(8px);width:auto}}@media only screen and (min-width:768px){.c-header__dropdown.has-tethered{min-width:225px}}.c-header__dropdown--full-width.has-tethered{padding:32px 0 24px;transform:none;width:100%}.has-tethered .c-header__heading--js-hide{display:none;visibility:hidden}.has-tethered .c-header__list--js-stack{flex-direction:column}.has-tethered .c-header__item--keyline,.has-tethered .c-header__list~.c-header__list .c-header__item:first-child{border-top:1px solid #d5d5d5;margin-top:8px;padding-top:8px}.c-header__item--snid-account-widget{display:flex}.c-header__container{padding:0 4px}.c-header__list{padding:0 12px}.c-header__menu .c-header__link{font-size:14px}.c-header__item--snid-account-widget .c-header__link{padding:8px}.c-header__menu--journal{margin-left:0}@media only screen and (min-width:540px){.c-header__container{padding:0 16px}.c-header__menu--journal{margin-left:-8px}.c-header__menu .c-header__link{font-size:16px}.c-header__link--search{gap:13px 13px}}.u-button{align-items:center;background-color:transparent;background-image:none;border:1px solid #069;border-radius:2px;color:#069;cursor:pointer;display:inline-flex;font-family:sans-serif;font-size:1rem;justify-content:center;line-height:1.3;margin:0;padding:8px;position:relative;text-decoration:none;transition:all .25s ease 0s,color .25s ease 0s,border-color .25s ease 0s;width:auto}.u-button--primary{background-color:#069;background-image:none;border:1px solid #069;color:#fff}.u-button--full-width{display:flex;width:100%}.u-display-none{display:none}.js .u-js-hide,.u-hide{display:none;visibility:hidden}.u-hide:first-child+*{margin-block-start:0}.u-visually-hidden{clip:rect(0,0,0,0);border:0;height:1px;margin:-100%;overflow:hidden;padding:0;position:absolute!important;width:1px}@media print{.u-hide-print{display:none}}@media only screen and (min-width:1024px){.u-hide-at-lg{display:none;visibility:hidden}.u-hide-at-lg:first-child+*{margin-block-start:0}}.u-clearfix:after,.u-clearfix:before{content:"";display:table}.u-clearfix:after{clear:both}.u-color-open-access{color:#b74616}.u-float-left{float:left}.u-icon{fill:currentcolor;display:inline-block;height:1em;transform:translate(0);vertical-align:text-top;width:1em}.u-full-height{height:100%}.u-list-reset{list-style:none;margin:0;padding:0}.u-sans-serif{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif}.u-container{margin:0 auto;max-width:1280px;padding:0 16px}.u-justify-content-space-between{justify-content:space-between}.u-mt-32{margin-top:32px}.u-mb-8{margin-bottom:8px}.u-mb-16{margin-bottom:16px}.u-mb-24{margin-bottom:24px}.u-mb-32{margin-bottom:32px}.c-nature-box svg+.c-article__button-text,.u-ml-8{margin-left:8px}.u-pa-16{padding:16px}html *,html :after,html :before{box-sizing:inherit}.c-article-section__title,.c-article-title{font-weight:700}.c-card__title{line-height:1.4em}.c-article__button{background-color:#069;border:1px solid #069;border-radius:2px;color:#fff;display:flex;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen-Sans,Ubuntu,Cantarell,Helvetica Neue,sans-serif;font-size:.875rem;line-height:1.4;margin-bottom:16px;padding:13px;transition:background-color .2s ease-out 0s,color .2s ease-out 0s}.c-article__button,.c-article__button:hover{text-decoration:none}.c-article__button--inverted,.c-article__button:hover{background-color:#fff;color:#069}.c-article__button--inverted:hover{background-color:#069;color:#fff}.c-header__link{text-decoration:inherit}.grade-c-hide{display:block}.u-lazy-ad-wrapper{background-color:#ccc;display:none;min-height:137px}@media only screen and (min-width:768px){.u-lazy-ad-wrapper{display:block}}.c-nature-box{background-color:#fff;border:1px solid #d5d5d5;border-radius:2px;box-shadow:0 0 5px 0 rgba(51,51,51,.1);line-height:1.3;margin-bottom:24px;padding:16px 16px 3px}.c-nature-box__text{font-size:1rem;margin-bottom:16px}.c-nature-box .c-pdf-download{margin-bottom:16px!important}.c-nature-box--version{background-color:#eee}.c-nature-box__wrapper{transform:translateZ(0)}.c-nature-box__wrapper--placeholder{min-height:165px}.c-pdf-download__link{padding:13px 24px} } </style> <link data-test="critical-css-handler" data-inline-css-source="critical-css" rel="stylesheet" href="/static/css/enhanced-article-nature-branded-d54f9178e8.css" media="print" onload="this.media='only print, only all and (prefers-color-scheme: no-preference), only all and (prefers-color-scheme: light), only all and (prefers-color-scheme: dark)';this.onload=null"> <noscript> <link rel="stylesheet" type="text/css" href="/static/css/enhanced-article-nature-branded-d54f9178e8.css" media="only print, only all and (prefers-color-scheme: no-preference), only all and (prefers-color-scheme: light), only all and (prefers-color-scheme: dark)"> </noscript> <link rel="stylesheet" type="text/css" href="/static/css/article-print-122346e276.css" media="print"> <link rel="apple-touch-icon" sizes="180x180" href=/static/images/favicons/nature/apple-touch-icon-f39cb19454.png> <link rel="icon" type="image/png" sizes="48x48" href=/static/images/favicons/nature/favicon-48x48-b52890008c.png> <link rel="icon" type="image/png" sizes="32x32" href=/static/images/favicons/nature/favicon-32x32-3fe59ece92.png> <link rel="icon" type="image/png" sizes="16x16" href=/static/images/favicons/nature/favicon-16x16-951651ab72.png> <link rel="manifest" href=/static/manifest.json crossorigin="use-credentials"> <link rel="mask-icon" href=/static/images/favicons/nature/safari-pinned-tab-69bff48fe6.svg color="#000000"> <link rel="shortcut icon" href=/static/images/favicons/nature/favicon.ico> <meta name="msapplication-TileColor" content="#000000"> <meta name="msapplication-config" content=/static/browserconfig.xml> <meta name="theme-color" content="#000000"> <meta name="application-name" content="Nature"> <script> (function () { if ( typeof window.CustomEvent === "function" ) return false; function CustomEvent ( event, params ) { params = params || { bubbles: false, cancelable: false, detail: null }; var evt = document.createEvent( 'CustomEvent' ); evt.initCustomEvent( event, params.bubbles, params.cancelable, params.detail ); return evt; } CustomEvent.prototype = window.Event.prototype; window.CustomEvent = CustomEvent; })(); </script>  <script data-test="gtm-head"> window.initGTM = function() { if (window.config.mustardcut) { (function (w, d, s, l, i) { w[l] = w[l] || []; w[l].push({'gtm.start': new Date().getTime(), event: 'gtm.js'}); var f = d.getElementsByTagName(s)[0], j = d.createElement(s), dl = l != 'dataLayer' ? '&l=' + l : ''; j.async = true; j.src = 'https://www.googletagmanager.com/gtm.js?id=' + i + dl; f.parentNode.insertBefore(j, f); })(window, document, 'script', 'dataLayer', 'GTM-MRVXSHQ'); } } </script>  <script> (function(w,d,t) { function cc() { var h = w.location.hostname; if (h.indexOf('preview-www.nature.com') > -1) return; var e = d.createElement(t), s = d.getElementsByTagName(t)[0]; if (h.indexOf('nature.com') > -1) { if (h.indexOf('test-www.nature.com') > -1) { e.src = 'https://cmp.nature.com/production_live/en/consent-bundle-8-74.js'; e.setAttribute('onload', "initGTM(window,document,'script','dataLayer','GTM-MRVXSHQ')"); } else { e.src = 'https://cmp.nature.com/production_live/en/consent-bundle-8-74.js'; e.setAttribute('onload', "initGTM(window,document,'script','dataLayer','GTM-MRVXSHQ')"); } } else { e.src = '/static/js/cookie-consent-es5-bundle-cb57c2c98a.js'; e.setAttribute('data-consent', h); } s.insertAdjacentElement('afterend', e); } cc(); })(window,document,'script'); </script> <script id="js-position0"> (function(w, d) { w.idpVerifyPrefix = 'https://verify.nature.com'; w.ra21Host = 'https://wayf.springernature.com'; var moduleSupport = (function() { return 'noModule' in d.createElement('script'); })(); if (w.config.mustardcut === true) { w.loader = { index: 0, registered: [], scripts: [ {src: '/static/js/global-article-es6-bundle-c8a573ca90.js', test: 'global-article-js', module: true}, {src: '/static/js/global-article-es5-bundle-d17603b9e9.js', test: 'global-article-js', nomodule: true}, {src: '/static/js/shared-es6-bundle-606cb67187.js', test: 'shared-js', module: true}, {src: '/static/js/shared-es5-bundle-e919764a53.js', test: 'shared-js', nomodule: true}, {src: '/static/js/header-150-es6-bundle-5bb959eaa1.js', test: 'header-150-js', module: true}, {src: '/static/js/header-150-es5-bundle-994fde5b1d.js', test: 'header-150-js', nomodule: true} ].filter(function (s) { if (s.src === null) return false; if (moduleSupport && s.nomodule) return false; return !(!moduleSupport && s.module); }), register: function (value) { this.registered.push(value); }, ready: function () { if (this.registered.length === this.scripts.length) { this.registered.forEach(function (fn) { if (typeof fn === 'function') { setTimeout(fn, 0); } }); this.ready = function () {}; } }, insert: function (s) { var t = d.getElementById('js-position' + this.index); if (t && t.insertAdjacentElement) { t.insertAdjacentElement('afterend', s); } else { d.head.appendChild(s); } ++this.index; }, createScript: function (script, beforeLoad) { var s = d.createElement('script'); s.id = 'js-position' + (this.index + 1); s.setAttribute('data-test', script.test); if (beforeLoad) { s.defer = 'defer'; s.onload = function () { if (script.noinit) { loader.register(true); } if (d.readyState === 'interactive' || d.readyState === 'complete') { loader.ready(); } }; } else { s.async = 'async'; } s.src = script.src; return s; }, init: function () { this.scripts.forEach(function (s) { loader.insert(loader.createScript(s, true)); }); d.addEventListener('DOMContentLoaded', function () { loader.ready(); var conditionalScripts; conditionalScripts = [ {match: 'div[data-pan-container]', src: '/static/js/pan-zoom-es6-bundle-464a2af269.js', test: 'pan-zoom-js', module: true }, {match: 'div[data-pan-container]', src: '/static/js/pan-zoom-es5-bundle-98fb9b653b.js', test: 'pan-zoom-js', nomodule: true }, {match: 'math,span.mathjax-tex', src: '/static/js/math-es6-bundle-23597ae350.js', test: 'math-js', module: true}, {match: 'math,span.mathjax-tex', src: '/static/js/math-es5-bundle-6532c6f78b.js', test: 'math-js', nomodule: true} ]; if (conditionalScripts) { conditionalScripts.filter(function (script) { return !!document.querySelector(script.match) && !((moduleSupport && script.nomodule) || (!moduleSupport && script.module)); }).forEach(function (script) { loader.insert(loader.createScript(script)); }); } }, false); } }; loader.init(); } })(window, document); </script> <meta name="robots" content="noarchive"> <meta name="access" content="Yes"> <link rel="search" href="https://www.nature.com/search"> <link rel="search" href="https://www.nature.com/opensearch/opensearch.xml" type="application/opensearchdescription+xml" title="nature.com"> <link rel="search" href="https://www.nature.com/opensearch/request" type="application/sru+xml" title="nature.com"> <script type="application/ld+json">{"mainEntity":{"headline":"Seeded X-ray free-electron laser generating radiation with laser statistical properties","description":"The invention of optical lasers led to a revolution in the field of optics and to the creation of such fields of research as quantum optics. The reason was their unique statistical and coherence properties. The emerging, short-wavelength free-electron lasers (FELs) are sources of very bright coherent extreme-ultraviolet and X-ray radiation with pulse durations on the order of femtoseconds, and are presently considered to be laser sources at these energies. FELs are highly spatially coherent to the first-order but in spite of their name, behave statistically as chaotic sources. Here, we demonstrate experimentally, by combining Hanbury Brown and Twiss interferometry with spectral measurements that the seeded XUV FERMI FEL-2 source does indeed behave statistically as a laser. The results may be useful for quantum optics experiments and for the design and operation of next generation FEL sources. Free electron lasers are emerging as important tools for nonlinear spectroscopy in the X-ray regime. Here the authors demonstrate the second order coherence of a seeded FEL source that may be useful for measurements in quantum optics.","datePublished":"2018-10-29T00:00:00Z","dateModified":"2019-11-13T00:00:00Z","pageStart":"1","pageEnd":"6","license":"http://creativecommons.org/licenses/by/4.0/","sameAs":"https://doi.org/10.1038/s41467-018-06743-8","keywords":["Free-electron lasers","Optical spectroscopy","Science","Humanities and Social Sciences","multidisciplinary"],"image":["https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig1_HTML.png","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig2_HTML.png","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig3_HTML.png","https://media.springernature.com/lw1200/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig4_HTML.png"],"isPartOf":{"name":"Nature Communications","issn":["2041-1723"],"volumeNumber":"9","@type":["Periodical","PublicationVolume"]},"publisher":{"name":"Nature Publishing Group UK","logo":{"url":"https://www.springernature.com/app-sn/public/images/logo-springernature.png","@type":"ImageObject"},"@type":"Organization"},"author":[{"name":"Oleg Yu. Gorobtsov","affiliation":[{"name":"Deutsches Elektronen-Synchrotron DESY","address":{"name":"Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany","@type":"PostalAddress"},"@type":"Organization"},{"name":"Cornell University","address":{"name":"Department of Materials Science and Engineering, Cornell University, Ithaca, USA","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Giuseppe Mercurio","affiliation":[{"name":"University of Hamburg and Center for Free Electron Laser Science","address":{"name":"Department of Physics, University of Hamburg and Center for Free Electron Laser Science, Hamburg, Germany","@type":"PostalAddress"},"@type":"Organization"},{"name":"Holzkoppel 4","address":{"name":"European XFEL GmbH, Holzkoppel 4, Schenefeld, Germany","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Flavio Capotondi","affiliation":[{"name":"Elettra-Sincrotrone Trieste","address":{"name":"Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Petr Skopintsev","affiliation":[{"name":"Deutsches Elektronen-Synchrotron DESY","address":{"name":"Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany","@type":"PostalAddress"},"@type":"Organization"},{"name":"Paul Scherrer Institute, PSI Aarebrucke","address":{"name":"Laboratory for Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, PSI Aarebrucke, Villigen, Switzerland","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Sergey Lazarev","url":"http://orcid.org/0000-0002-7230-3559","affiliation":[{"name":"Deutsches Elektronen-Synchrotron DESY","address":{"name":"Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany","@type":"PostalAddress"},"@type":"Organization"},{"name":"National Research Tomsk Polytechnic University (TPU)","address":{"name":"National Research Tomsk Polytechnic University (TPU), Tomsk, Russia","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Ivan A. Zaluzhnyy","url":"http://orcid.org/0000-0001-5946-2777","affiliation":[{"name":"Deutsches Elektronen-Synchrotron DESY","address":{"name":"Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany","@type":"PostalAddress"},"@type":"Organization"},{"name":"National Research Nuclear University MEPhI (Moscow Engineering Physics Institute)","address":{"name":"National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow, Russia","@type":"PostalAddress"},"@type":"Organization"},{"name":"University of California San Diego","address":{"name":"Department of Physics, University of California San Diego, La Jolla CA, USA","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Miltcho B. Danailov","affiliation":[{"name":"Elettra-Sincrotrone Trieste","address":{"name":"Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Martina Dell’Angela","affiliation":[{"name":"CNR- IOM Istituto Officina dei Materiali","address":{"name":"CNR- IOM Istituto Officina dei Materiali, Trieste, Italy","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Michele Manfredda","affiliation":[{"name":"Elettra-Sincrotrone Trieste","address":{"name":"Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Emanuele Pedersoli","url":"http://orcid.org/0000-0003-0572-6735","affiliation":[{"name":"Elettra-Sincrotrone Trieste","address":{"name":"Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Luca Giannessi","affiliation":[{"name":"Elettra-Sincrotrone Trieste","address":{"name":"Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy","@type":"PostalAddress"},"@type":"Organization"},{"name":"ENEA C.R. Frascati","address":{"name":"ENEA C.R. Frascati, Frascati, Italy","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Maya Kiskinova","url":"http://orcid.org/0000-0001-9584-3526","affiliation":[{"name":"Elettra-Sincrotrone Trieste","address":{"name":"Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Kevin C. Prince","url":"http://orcid.org/0000-0002-5416-7354","affiliation":[{"name":"Elettra-Sincrotrone Trieste","address":{"name":"Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy","@type":"PostalAddress"},"@type":"Organization"},{"name":"School of Science Swinburne University of Technology","address":{"name":"Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, School of Science Swinburne University of Technology, Melbourne, Australia","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Wilfried Wurth","affiliation":[{"name":"Deutsches Elektronen-Synchrotron DESY","address":{"name":"Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany","@type":"PostalAddress"},"@type":"Organization"},{"name":"University of Hamburg and Center for Free Electron Laser Science","address":{"name":"Department of Physics, University of Hamburg and Center for Free Electron Laser Science, Hamburg, Germany","@type":"PostalAddress"},"@type":"Organization"}],"@type":"Person"},{"name":"Ivan A. Vartanyants","url":"http://orcid.org/0000-0002-0340-8234","affiliation":[{"name":"Deutsches Elektronen-Synchrotron DESY","address":{"name":"Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany","@type":"PostalAddress"},"@type":"Organization"},{"name":"National Research Nuclear University MEPhI (Moscow Engineering Physics Institute)","address":{"name":"National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow, Russia","@type":"PostalAddress"},"@type":"Organization"}],"email":"ivan.vartaniants@desy.de","@type":"Person"}],"isAccessibleForFree":true,"@type":"ScholarlyArticle"},"@context":"https://schema.org","@type":"WebPage"}</script> <link rel="canonical" href="https://www.nature.com/articles/s41467-018-06743-8"> <meta name="journal_id" content="41467"/> <meta name="dc.title" content="Seeded X-ray free-electron laser generating radiation with laser statistical properties"/> <meta name="dc.source" content="Nature Communications 2018 9:1"/> <meta name="dc.format" content="text/html"/> <meta name="dc.publisher" content="Nature Publishing Group"/> <meta name="dc.date" content="2018-10-29"/> <meta name="dc.type" content="OriginalPaper"/> <meta name="dc.language" content="En"/> <meta name="dc.copyright" content="2018 The Author(s)"/> <meta name="dc.rights" content="2018 The Author(s)"/> <meta name="dc.rightsAgent" content="journalpermissions@springernature.com"/> <meta name="dc.description" content="The invention of optical lasers led to a revolution in the field of optics and to the creation of such fields of research as quantum optics. The reason was their unique statistical and coherence properties. The emerging, short-wavelength free-electron lasers (FELs) are sources of very bright coherent extreme-ultraviolet and X-ray radiation with pulse durations on the order of femtoseconds, and are presently considered to be laser sources at these energies. FELs are highly spatially coherent to the first-order but in spite of their name, behave statistically as chaotic sources. Here, we demonstrate experimentally, by combining Hanbury Brown and Twiss interferometry with spectral measurements that the seeded XUV FERMI FEL-2 source does indeed behave statistically as a laser. The results may be useful&nbsp;for quantum optics experiments and for the design and operation of next generation FEL sources. Free electron lasers are emerging as important tools for nonlinear spectroscopy in the X-ray regime. Here the authors demonstrate the second order coherence of a seeded FEL source that may be useful for measurements in quantum optics."/> <meta name="prism.issn" content="2041-1723"/> <meta name="prism.publicationName" content="Nature Communications"/> <meta name="prism.publicationDate" content="2018-10-29"/> <meta name="prism.volume" content="9"/> <meta name="prism.number" content="1"/> <meta name="prism.section" content="OriginalPaper"/> <meta name="prism.startingPage" content="1"/> <meta name="prism.endingPage" content="6"/> <meta name="prism.copyright" content="2018 The Author(s)"/> <meta name="prism.rightsAgent" content="journalpermissions@springernature.com"/> <meta name="prism.url" content="https://www.nature.com/articles/s41467-018-06743-8"/> <meta name="prism.doi" content="doi:10.1038/s41467-018-06743-8"/> <meta name="citation_pdf_url" content="https://www.nature.com/articles/s41467-018-06743-8.pdf"/> <meta name="citation_fulltext_html_url" content="https://www.nature.com/articles/s41467-018-06743-8"/> <meta name="citation_journal_title" content="Nature Communications"/> <meta name="citation_journal_abbrev" content="Nat Commun"/> <meta name="citation_publisher" content="Nature Publishing Group"/> <meta name="citation_issn" content="2041-1723"/> <meta name="citation_title" content="Seeded X-ray free-electron laser generating radiation with laser statistical properties"/> <meta name="citation_volume" content="9"/> <meta name="citation_issue" content="1"/> <meta name="citation_online_date" content="2018/10/29"/> <meta name="citation_firstpage" content="1"/> <meta name="citation_lastpage" content="6"/> <meta name="citation_article_type" content="Article"/> <meta name="citation_fulltext_world_readable" content=""/> <meta name="citation_language" content="en"/> <meta name="dc.identifier" content="doi:10.1038/s41467-018-06743-8"/> <meta name="DOI" content="10.1038/s41467-018-06743-8"/> <meta name="size" content="110730"/> <meta name="citation_doi" content="10.1038/s41467-018-06743-8"/> <meta name="citation_springer_api_url" content="http://api.springer.com/xmldata/jats?q=doi:10.1038/s41467-018-06743-8&api_key="/> <meta name="description" content="The invention of optical lasers led to a revolution in the field of optics and to the creation of such fields of research as quantum optics. The reason was their unique statistical and coherence properties. The emerging, short-wavelength free-electron lasers (FELs) are sources of very bright coherent extreme-ultraviolet and X-ray radiation with pulse durations on the order of femtoseconds, and are presently considered to be laser sources at these energies. FELs are highly spatially coherent to the first-order but in spite of their name, behave statistically as chaotic sources. Here, we demonstrate experimentally, by combining Hanbury Brown and Twiss interferometry with spectral measurements that the seeded XUV FERMI FEL-2 source does indeed behave statistically as a laser. The results may be useful&nbsp;for quantum optics experiments and for the design and operation of next generation FEL sources. Free electron lasers are emerging as important tools for nonlinear spectroscopy in the X-ray regime. Here the authors demonstrate the second order coherence of a seeded FEL source that may be useful for measurements in quantum optics."/> <meta name="dc.creator" content="Gorobtsov, Oleg Yu."/> <meta name="dc.creator" content="Mercurio, Giuseppe"/> <meta name="dc.creator" content="Capotondi, Flavio"/> <meta name="dc.creator" content="Skopintsev, Petr"/> <meta name="dc.creator" content="Lazarev, Sergey"/> <meta name="dc.creator" content="Zaluzhnyy, Ivan A."/> <meta name="dc.creator" content="Danailov, Miltcho B."/> <meta name="dc.creator" content="Dell’Angela, Martina"/> <meta name="dc.creator" content="Manfredda, Michele"/> <meta name="dc.creator" content="Pedersoli, Emanuele"/> <meta name="dc.creator" content="Giannessi, Luca"/> <meta name="dc.creator" content="Kiskinova, Maya"/> <meta name="dc.creator" content="Prince, Kevin C."/> <meta name="dc.creator" content="Wurth, Wilfried"/> <meta name="dc.creator" content="Vartanyants, Ivan A."/> <meta name="dc.subject" content="Free-electron lasers"/> <meta name="dc.subject" content="Optical spectroscopy"/> <meta name="citation_reference" content="citation_journal_title=Phys. Rev.; citation_title=The quantum theory of optical coherence; citation_author=RJ Glauber; citation_volume=130; citation_publication_date=1963; citation_pages=2529-2539; citation_doi=10.1103/PhysRev.130.2529; citation_id=CR1"/> <meta name="citation_reference" content="citation_journal_title=Phys. Lett.; citation_title=Time distribution of photons from coherent and Gaussian sources; citation_author=FT Arecchi, E Gatti, A Sona; citation_volume=20; citation_publication_date=1966; citation_pages=27-29; citation_doi=10.1016/0031-9163(66)91034-1; citation_id=CR2"/> <meta name="citation_reference" content="citation_title=The Quantum Theory of Light; citation_publication_date=2000; citation_id=CR3; citation_author=R Loudon; citation_publisher=Oxford University Press"/> <meta name="citation_reference" content="citation_journal_title=Phys. Rev. Lett.; citation_title=Directional superradiant emission from statistically independent incoherent nonclassical and classical sources; citation_author=S Oppel, R Wiegner, GS Agarwal, J Zanthier; citation_volume=113; citation_publication_date=2014; citation_pages=263606; citation_doi=10.1103/PhysRevLett.113.263606; citation_id=CR4"/> <meta name="citation_reference" content="citation_journal_title=Nat. Phys.; citation_title=Quantum imaging with incoherently scattered light from a free-electron laser; citation_author=R Schneider; citation_volume=14; citation_publication_date=2018; citation_pages=126-129; citation_doi=10.1038/nphys4301; citation_id=CR5"/> <meta name="citation_reference" content="citation_journal_title=Nat. Photon.; citation_title=Operation of a free-electron laser from the extreme ultraviolet to the water window; citation_author=W Ackermann; citation_volume=1; citation_publication_date=2007; citation_pages=336-342; citation_doi=10.1038/nphoton.2007.76; citation_id=CR6"/> <meta name="citation_reference" content="citation_journal_title=Nat. Photon.; citation_title=Two-stage seeded soft-X-ray free-electron laser; citation_author=E Allaria; citation_volume=7; citation_publication_date=2013; citation_pages=913-918; citation_doi=10.1038/nphoton.2013.277; citation_id=CR7"/> <meta name="citation_reference" content="citation_journal_title=Nat. Photon.; citation_title=First lasing and operation of an ångstrom-wavelength free-electron laser; citation_author=P Emma; citation_volume=4; citation_publication_date=2010; citation_pages=641-647; citation_doi=10.1038/nphoton.2010.176; citation_id=CR8"/> <meta name="citation_reference" content="citation_journal_title=Nat. Photon.; citation_title=A compact x-ray free-electron laser emitting in the sub-angstrom region; citation_author=T Ishikawa; citation_volume=6; citation_publication_date=2012; citation_pages=540-544; citation_doi=10.1038/nphoton.2012.141; citation_id=CR9"/> <meta name="citation_reference" content="Altarelli, M. et al. The European X-ray Free-electron Laser—technical Design Report. Technical Report DESY 2006-097. European XFEL Project Team (Deutsches Elektronen-Synchrotron, Hamburg, 2006)."/> <meta name="citation_reference" content="citation_title=The Physics of Free Electron Laser; citation_publication_date=2000; citation_id=CR11; citation_author=E Saldin; citation_author=E Schneidmiller; citation_author=M Yurkov; citation_publisher=Springer-Verlag"/> <meta name="citation_reference" content="citation_journal_title=Phys. Rev. Lett.; citation_title=Coherence properties of individual femtosecond pulses of an x-ray free-electron laser; citation_author=IA Vartanyants; citation_volume=107; citation_publication_date=2011; citation_pages=144801; citation_doi=10.1103/PhysRevLett.107.144801; citation_id=CR12"/> <meta name="citation_reference" content="citation_journal_title=Opt. Express; citation_title=Spatial and temporal coherence properties of single free-electron laser pulses; citation_author=A Singer; citation_volume=20; citation_publication_date=2012; citation_pages=17480-17495; citation_doi=10.1364/OE.20.017480; citation_id=CR13"/> <meta name="citation_reference" content="citation_journal_title=Phys. Rev. Lett.; citation_title=Hanbury Brown-Twiss interferometry at a free-electron laser; citation_author=A Singer; citation_volume=111; citation_publication_date=2013; citation_pages=034802; citation_doi=10.1103/PhysRevLett.111.034802; citation_id=CR14"/> <meta name="citation_reference" content="citation_journal_title=Phys. Rev. A; citation_title=Statistical properties of a free-electron laser revealed by Hanbury Brown-Twiss interferometry; citation_author=OYu Gorobtsov; citation_volume=95; citation_publication_date=2017; citation_pages=023843; citation_doi=10.1103/PhysRevA.95.023843; citation_id=CR15"/> <meta name="citation_reference" content="citation_journal_title=Sci. Rep.; citation_title=Diffraction based Hanbury Brown and Twiss interferometry performed at a hard x-ray free-electron laser; citation_author=OYu Gorobtsov; citation_volume=8; citation_publication_date=2018; citation_doi=10.1038/s41598-018-19793-1; citation_id=CR16"/> <meta name="citation_reference" content="citation_journal_title=Nat. Photon.; citation_title=Coherent control with a short-wavelength free-electron laser; citation_author=KC Prince; citation_volume=10; citation_publication_date=2016; citation_pages=176-179; citation_doi=10.1038/nphoton.2016.13; citation_id=CR17"/> <meta name="citation_reference" content="citation_journal_title=Nat. Commun.; citation_title=Attosecond interferometry with self-amplified spontaneous emission of a free-electron laser; citation_author=S Usenko; citation_volume=8; citation_publication_date=2017; citation_pages=15626; citation_doi=10.1038/ncomms15626; citation_id=CR18"/> <meta name="citation_reference" content="citation_journal_title=Nat. Commun.; citation_title=Single-shot spectro-temporal characterization of XUV pulses from a seeded free-electron laser; citation_author=GD Ninno; citation_volume=6; citation_publication_date=2015; citation_pages=8075; citation_doi=10.1038/ncomms9075; citation_id=CR19"/> <meta name="citation_reference" content="citation_journal_title=Phys. Rev. Lett.; citation_title=Spectrotemporal shaping of seeded free-electron laser pulses; citation_author=D Gauthier; citation_volume=115; citation_publication_date=2015; citation_pages=114801; citation_doi=10.1103/PhysRevLett.115.114801; citation_id=CR20"/> <meta name="citation_reference" content="citation_journal_title=Nature; citation_title=Correlation between photons in two coherent beams of light; citation_author=R Hanbury Brown, RQ Twiss; citation_volume=177; citation_publication_date=1956; citation_pages=27-32; citation_doi=10.1038/177027a0; citation_id=CR21"/> <meta name="citation_reference" content="citation_journal_title=Nature; citation_title=A test of a new type of stellar interferometer on Sirius; citation_author=R Hanbury Brown, RQ Twiss; citation_volume=178; citation_publication_date=1956; citation_pages=1046-1048; citation_doi=10.1038/1781046a0; citation_id=CR22"/> <meta name="citation_reference" content="citation_journal_title=Rev. Mod. Phys.; citation_title=Interference between independent photons; citation_author=H Paul; citation_volume=58; citation_publication_date=1986; citation_pages=209-231; citation_doi=10.1103/RevModPhys.58.209; citation_id=CR23"/> <meta name="citation_reference" content="citation_journal_title=Photonics; citation_title=Optical Klystron enhancement to self amplified spontaneous emission at FERMI; citation_author=G Penco; citation_volume=4; citation_publication_date=2017; citation_pages=15; citation_doi=10.3390/photonics4010015; citation_id=CR24"/> <meta name="citation_reference" content="citation_title=Statistical Optics; citation_publication_date=2000; citation_id=CR25; citation_author=JW Goodman; citation_publisher=Wiley"/> <meta name="citation_reference" content="citation_journal_title=Phys. Rev. Lett.; citation_title=Unequivocal differentiation of coherent and chaotic light through interferometric photon correlation measurements; citation_author=A Lebreton; citation_volume=110; citation_publication_date=2013; citation_pages=163603; citation_doi=10.1103/PhysRevLett.110.163603; citation_id=CR26"/> <meta name="citation_reference" content="citation_journal_title=Phys. Rev. Lett.; citation_title=Measurement of subpicosecond time intervals between two photons by interference; citation_author=CK Hong, ZY Ou, L Mandel; citation_volume=59; citation_publication_date=1987; citation_pages=2044; citation_doi=10.1103/PhysRevLett.59.2044; citation_id=CR27"/> <meta name="citation_reference" content="citation_journal_title=Phys. Rev. Lett.; citation_title=Two-photon X-ray diffraction; citation_author=J Stöhr; citation_volume=118; citation_publication_date=2017; citation_pages=024801; citation_doi=10.1103/PhysRevLett.118.024801; citation_id=CR28"/> <meta name="citation_reference" content="citation_journal_title=J. Mod. Opt.; citation_title=A novel self-seeding scheme for hard x-ray FELs; citation_author=G Geloni, V Kocharyan, E Saldin; citation_volume=58; citation_publication_date=2011; citation_pages=1391-1403; citation_doi=10.1080/09500340.2011.586473; citation_id=CR29"/> <meta name="citation_reference" content="citation_journal_title=Nat. Photon.; citation_title=Demonstration of self-seeding in a hard-X-ray free-electron laser; citation_author=J Amann; citation_volume=6; citation_publication_date=2012; citation_pages=693-698; citation_doi=10.1038/nphoton.2012.180; citation_id=CR30"/> <meta name="citation_reference" content="citation_journal_title=Phys. Rev. Lett.; citation_title=Interference effects between independent gamma rays; citation_author=E Ikonen; citation_volume=68; citation_publication_date=1992; citation_pages=2759-2761; citation_doi=10.1103/PhysRevLett.68.2759; citation_id=CR31"/> <meta name="citation_reference" content="citation_journal_title=J. Synchrotron Rad.; citation_title=PRESTO, the on-line photon energy spectrometer at FERMI: design, features and commissioning results; citation_author=C Svetina; citation_volume=23; citation_publication_date=2016; citation_pages=35-42; citation_doi=10.1107/S1600577515021116; citation_id=CR32"/> <meta name="citation_reference" content="citation_journal_title=Opt. Comm.; citation_title=Statistical properties of radiation from VUV and x-ray free electron laser; citation_author=E Saldin, E Schneidmiller, M Yurkov; citation_volume=148; citation_publication_date=1998; citation_pages=383-403; citation_doi=10.1016/S0030-4018(97)00670-6; citation_id=CR33"/> <meta name="citation_author" content="Gorobtsov, Oleg Yu."/> <meta name="citation_author_institution" content="Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany"/> <meta name="citation_author_institution" content="Department of Materials Science and Engineering, Cornell University, Ithaca, USA"/> <meta name="citation_author" content="Mercurio, Giuseppe"/> <meta name="citation_author_institution" content="Department of Physics, University of Hamburg and Center for Free Electron Laser Science, Hamburg, Germany"/> <meta name="citation_author_institution" content="European XFEL GmbH, Holzkoppel 4, Schenefeld, Germany"/> <meta name="citation_author" content="Capotondi, Flavio"/> <meta name="citation_author_institution" content="Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy"/> <meta name="citation_author" content="Skopintsev, Petr"/> <meta name="citation_author_institution" content="Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany"/> <meta name="citation_author_institution" content="Laboratory for Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, PSI Aarebrucke, Villigen, Switzerland"/> <meta name="citation_author" content="Lazarev, Sergey"/> <meta name="citation_author_institution" content="Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany"/> <meta name="citation_author_institution" content="National Research Tomsk Polytechnic University (TPU), Tomsk, Russia"/> <meta name="citation_author" content="Zaluzhnyy, Ivan A."/> <meta name="citation_author_institution" content="Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany"/> <meta name="citation_author_institution" content="National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow, Russia"/> <meta name="citation_author_institution" content="Department of Physics, University of California San Diego, La Jolla CA, USA"/> <meta name="citation_author" content="Danailov, Miltcho B."/> <meta name="citation_author_institution" content="Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy"/> <meta name="citation_author" content="Dell’Angela, Martina"/> <meta name="citation_author_institution" content="CNR- IOM Istituto Officina dei Materiali, Trieste, Italy"/> <meta name="citation_author" content="Manfredda, Michele"/> <meta name="citation_author_institution" content="Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy"/> <meta name="citation_author" content="Pedersoli, Emanuele"/> <meta name="citation_author_institution" content="Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy"/> <meta name="citation_author" content="Giannessi, Luca"/> <meta name="citation_author_institution" content="Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy"/> <meta name="citation_author_institution" content="ENEA C.R. Frascati, Frascati, Italy"/> <meta name="citation_author" content="Kiskinova, Maya"/> <meta name="citation_author_institution" content="Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy"/> <meta name="citation_author" content="Prince, Kevin C."/> <meta name="citation_author_institution" content="Elettra-Sincrotrone Trieste, Basovizza (Trieste), Italy"/> <meta name="citation_author_institution" content="Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, School of Science Swinburne University of Technology, Melbourne, Australia"/> <meta name="citation_author" content="Wurth, Wilfried"/> <meta name="citation_author_institution" content="Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany"/> <meta name="citation_author_institution" content="Department of Physics, University of Hamburg and Center for Free Electron Laser Science, Hamburg, Germany"/> <meta name="citation_author" content="Vartanyants, Ivan A."/> <meta name="citation_author_institution" content="Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany"/> <meta name="citation_author_institution" content="National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow, Russia"/> <meta name="access_endpoint" content="https://www.nature.com/platform/readcube-access"/> <meta name="twitter:site" content="@NatureComms"/> <meta name="twitter:card" content="summary_large_image"/> <meta name="twitter:image:alt" content="Content cover image"/> <meta name="twitter:title" content="Seeded X-ray free-electron laser generating radiation with laser statistical properties"/> <meta name="twitter:description" content="Nature Communications - Free electron lasers are emerging as important tools for nonlinear spectroscopy in the X-ray regime. Here the authors demonstrate the second order coherence of a seeded FEL..."/> <meta name="twitter:image" content="https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig1_HTML.png"/> <meta property="og:url" content="https://www.nature.com/articles/s41467-018-06743-8"/> <meta property="og:type" content="article"/> <meta property="og:site_name" content="Nature"/> <meta property="og:title" content="Seeded X-ray free-electron laser generating radiation with laser statistical properties - Nature Communications"/> <meta property="og:description" content="Free electron lasers are emerging as important tools for nonlinear spectroscopy in the X-ray regime. Here the authors demonstrate the second order coherence of a seeded FEL source that may be useful for measurements in quantum optics."/> <meta property="og:image" content="https://media.springernature.com/m685/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig1_HTML.png"/> <script> window.eligibleForRa21 = 'false'; </script> </head> <body class="article-page"> <noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-MRVXSHQ" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript> <div class="position-relative cleared z-index-50 background-white" data-test="top-containers"> <a class="c-skip-link" href="#content">Skip to main content</a> <div class="c-grade-c-banner u-hide"> <div class="c-grade-c-banner__container"> <p>Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.</p> </div> </div> <div class="u-hide u-show-following-ad"></div> <aside class="c-ad c-ad--728x90"> <div class="c-ad__inner" data-container-type="banner-advert"> <p class="c-ad__label">Advertisement</p> <div id="div-gpt-ad-top-1" class="div-gpt-ad advert leaderboard js-ad text-center hide-print grade-c-hide" data-ad-type="top" data-test="top-ad" data-pa11y-ignore data-gpt data-gpt-unitpath="/285/nature_communications/article" data-gpt-sizes="728x90" data-gpt-targeting="type=article;pos=top;artid=s41467-018-06743-8;doi=10.1038/s41467-018-06743-8;techmeta=124,132,145;subjmeta=1020,1087,1107,527,624,639;kwrd=Free-electron+lasers,Optical+spectroscopy"> <noscript> <a href="//pubads.g.doubleclick.net/gampad/jump?iu=/285/nature_communications/article&sz=728x90&c=-265933502&t=pos%3Dtop%26type%3Darticle%26artid%3Ds41467-018-06743-8%26doi%3D10.1038/s41467-018-06743-8%26techmeta%3D124,132,145%26subjmeta%3D1020,1087,1107,527,624,639%26kwrd%3DFree-electron+lasers,Optical+spectroscopy"> <img data-test="gpt-advert-fallback-img" src="//pubads.g.doubleclick.net/gampad/ad?iu=/285/nature_communications/article&sz=728x90&c=-265933502&t=pos%3Dtop%26type%3Darticle%26artid%3Ds41467-018-06743-8%26doi%3D10.1038/s41467-018-06743-8%26techmeta%3D124,132,145%26subjmeta%3D1020,1087,1107,527,624,639%26kwrd%3DFree-electron+lasers,Optical+spectroscopy" alt="Advertisement" width="728" height="90"></a> </noscript> </div> </div> </aside> <header class="c-header" id="header" data-header data-track-component="nature-150-split-header" style="border-color:#e63323"> <div class="c-header__row"> <div class="c-header__container"> <div class="c-header__split"> <div class="c-header__logo-container"> <a href="/ncomms" data-track="click" data-track-action="home" data-track-label="image"> <picture class="c-header__logo"> <source srcset="https://media.springernature.com/full/nature-cms/uploads/product/ncomms/header-03d2e325c0a02f6df509e5730e9be304.svg" media="(min-width: 875px)"> <img src="https://media.springernature.com/full/nature-cms/uploads/product/ncomms/header-7001f06bc3fe2437048388e9f2f44215.svg" height="32" alt="Nature Communications"> </picture> </a> </div> <ul class="c-header__menu c-header__menu--global"> <li class="c-header__item c-header__item--padding c-header__item--hide-md-max"> <a class="c-header__link" href="https://www.nature.com/siteindex" data-test="siteindex-link" data-track="click" data-track-action="open nature research index" data-track-label="link"> <span>View all journals</span> </a> </li> <li class="c-header__item c-header__item--padding c-header__item--pipe"> <a class="c-header__link c-header__link--search" href="#search-menu" data-header-expander data-test="search-link" data-track="click" data-track-action="open search tray" data-track-label="button"> <svg role="img" aria-hidden="true" focusable="false" height="22" width="22" viewBox="0 0 18 18" xmlns="http://www.w3.org/2000/svg"><path d="M16.48 15.455c.283.282.29.749.007 1.032a.738.738 0 01-1.032-.007l-3.045-3.044a7 7 0 111.026-1.026zM8 14A6 6 0 108 2a6 6 0 000 12z"/></svg><span>Search</span> </a> </li> <li class="c-header__item c-header__item--padding c-header__item--snid-account-widget c-header__item--pipe"> <a class="c-header__link eds-c-header__link" id="identity-account-widget" data-track="click_login" data-track-context="header" href='https://idp.nature.com/auth/personal/springernature?redirect_uri=https://www.nature.com/articles/s41467-018-06743-8?error=cookies_not_supported&code=e00a70ab-1b53-4698-a8d9-515c95e87318'><span class="eds-c-header__widget-fragment-title">Log in</span></a> </li> </ul> </div> </div> </div> <div class="c-header__row"> <div class="c-header__container" data-test="navigation-row"> <div class="c-header__split"> <ul class="c-header__menu c-header__menu--journal"> <li class="c-header__item c-header__item--dropdown-menu" data-test="explore-content-button"> <a href="#explore" class="c-header__link" data-header-expander data-test="menu-button--explore" data-track="click" data-track-action="open explore expander" data-track-label="button"> <span><span class="c-header__show-text">Explore</span> content</span><svg role="img" aria-hidden="true" focusable="false" height="16" viewBox="0 0 16 16" width="16" xmlns="http://www.w3.org/2000/svg"><path d="m5.58578644 3-3.29289322-3.29289322c-.39052429-.39052429-.39052429-1.02368927 0-1.41421356s1.02368927-.39052429 1.41421356 0l4 4c.39052429.39052429.39052429 1.02368927 0 1.41421356l-4 4c-.39052429.39052429-1.02368927.39052429-1.41421356 0s-.39052429-1.02368927 0-1.41421356z" transform="matrix(0 1 -1 0 11 3)"/></svg> </a> </li> <li class="c-header__item c-header__item--dropdown-menu"> <a href="#about-the-journal" class="c-header__link" data-header-expander data-test="menu-button--about-the-journal" data-track="click" data-track-action="open about the journal expander" data-track-label="button"> <span>About <span class="c-header__show-text">the journal</span></span><svg role="img" aria-hidden="true" focusable="false" height="16" viewBox="0 0 16 16" width="16" xmlns="http://www.w3.org/2000/svg"><path d="m5.58578644 3-3.29289322-3.29289322c-.39052429-.39052429-.39052429-1.02368927 0-1.41421356s1.02368927-.39052429 1.41421356 0l4 4c.39052429.39052429.39052429 1.02368927 0 1.41421356l-4 4c-.39052429.39052429-1.02368927.39052429-1.41421356 0s-.39052429-1.02368927 0-1.41421356z" transform="matrix(0 1 -1 0 11 3)"/></svg> </a> </li> <li class="c-header__item c-header__item--dropdown-menu" data-test="publish-with-us-button"> <a href="#publish-with-us" class="c-header__link c-header__link--dropdown-menu" data-header-expander data-test="menu-button--publish" data-track="click" data-track-action="open publish with us expander" data-track-label="button"> <span>Publish <span class="c-header__show-text">with us</span></span><svg role="img" aria-hidden="true" focusable="false" height="16" viewBox="0 0 16 16" width="16" xmlns="http://www.w3.org/2000/svg"><path d="m5.58578644 3-3.29289322-3.29289322c-.39052429-.39052429-.39052429-1.02368927 0-1.41421356s1.02368927-.39052429 1.41421356 0l4 4c.39052429.39052429.39052429 1.02368927 0 1.41421356l-4 4c-.39052429.39052429-1.02368927.39052429-1.41421356 0s-.39052429-1.02368927 0-1.41421356z" transform="matrix(0 1 -1 0 11 3)"/></svg> </a> </li> </ul> <ul class="c-header__menu c-header__menu--hide-lg-max"> <li class="c-header__item"> <a class="c-header__link" href="https://idp.nature.com/auth/personal/springernature?redirect_uri=https%3A%2F%2Fwww.nature.com%2Fmy-account%2Falerts%2Fsubscribe-journal%3Flist-id%3D264%26journal-link%3Dhttps%253A%252F%252Fwww.nature.com%252Fncomms%252F" rel="nofollow" data-track="click" data-track-action="Sign up for alerts" data-track-label="link (desktop site header)" data-track-external> <span>Sign up for alerts</span><svg role="img" aria-hidden="true" focusable="false" height="18" viewBox="0 0 18 18" width="18" xmlns="http://www.w3.org/2000/svg"><path d="m4 10h2.5c.27614237 0 .5.2238576.5.5s-.22385763.5-.5.5h-3.08578644l-1.12132034 1.1213203c-.18753638.1875364-.29289322.4418903-.29289322.7071068v.1715729h14v-.1715729c0-.2652165-.1053568-.5195704-.2928932-.7071068l-1.7071068-1.7071067v-3.4142136c0-2.76142375-2.2385763-5-5-5-2.76142375 0-5 2.23857625-5 5zm3 4c0 1.1045695.8954305 2 2 2s2-.8954305 2-2zm-5 0c-.55228475 0-1-.4477153-1-1v-.1715729c0-.530433.21071368-1.0391408.58578644-1.4142135l1.41421356-1.4142136v-3c0-3.3137085 2.6862915-6 6-6s6 2.6862915 6 6v3l1.4142136 1.4142136c.3750727.3750727.5857864.8837805.5857864 1.4142135v.1715729c0 .5522847-.4477153 1-1 1h-4c0 1.6568542-1.3431458 3-3 3-1.65685425 0-3-1.3431458-3-3z" fill="#222"/></svg> </a> </li> <li class="c-header__item c-header__item--pipe"> <a class="c-header__link" href="https://www.nature.com/ncomms.rss" data-track="click" data-track-action="rss feed" data-track-label="link"> <span>RSS feed</span> </a> </li> </ul> </div> </div> </div> </header> <nav class="u-mb-16" aria-label="breadcrumbs"> <div class="u-container"> <ol class="c-breadcrumbs" itemscope itemtype="https://schema.org/BreadcrumbList"> <li class="c-breadcrumbs__item" id="breadcrumb0" itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem"><a class="c-breadcrumbs__link" href="/" itemprop="item" data-track="click" data-track-action="breadcrumb" data-track-category="header" data-track-label="link:nature"><span itemprop="name">nature</span></a><meta itemprop="position" content="1"> <svg class="c-breadcrumbs__chevron" role="img" aria-hidden="true" focusable="false" height="10" viewBox="0 0 10 10" width="10" xmlns="http://www.w3.org/2000/svg"> <path d="m5.96738168 4.70639573 2.39518594-2.41447274c.37913917-.38219212.98637524-.38972225 1.35419292-.01894278.37750606.38054586.37784436.99719163-.00013556 1.37821513l-4.03074001 4.06319683c-.37758093.38062133-.98937525.38100976-1.367372-.00003075l-4.03091981-4.06337806c-.37759778-.38063832-.38381821-.99150444-.01600053-1.3622839.37750607-.38054587.98772445-.38240057 1.37006824.00302197l2.39538588 2.4146743.96295325.98624457z" fill="#666" fill-rule="evenodd" transform="matrix(0 -1 1 0 0 10)"/> </svg> </li><li class="c-breadcrumbs__item" id="breadcrumb1" itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem"><a class="c-breadcrumbs__link" href="/ncomms" itemprop="item" data-track="click" data-track-action="breadcrumb" data-track-category="header" data-track-label="link:nature communications"><span itemprop="name">nature communications</span></a><meta itemprop="position" content="2"> <svg class="c-breadcrumbs__chevron" role="img" aria-hidden="true" focusable="false" height="10" viewBox="0 0 10 10" width="10" xmlns="http://www.w3.org/2000/svg"> <path d="m5.96738168 4.70639573 2.39518594-2.41447274c.37913917-.38219212.98637524-.38972225 1.35419292-.01894278.37750606.38054586.37784436.99719163-.00013556 1.37821513l-4.03074001 4.06319683c-.37758093.38062133-.98937525.38100976-1.367372-.00003075l-4.03091981-4.06337806c-.37759778-.38063832-.38381821-.99150444-.01600053-1.3622839.37750607-.38054587.98772445-.38240057 1.37006824.00302197l2.39538588 2.4146743.96295325.98624457z" fill="#666" fill-rule="evenodd" transform="matrix(0 -1 1 0 0 10)"/> </svg> </li><li class="c-breadcrumbs__item" id="breadcrumb2" itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem"><a class="c-breadcrumbs__link" href="/ncomms/articles?type=article" itemprop="item" data-track="click" data-track-action="breadcrumb" data-track-category="header" data-track-label="link:articles"><span itemprop="name">articles</span></a><meta itemprop="position" content="3"> <svg class="c-breadcrumbs__chevron" role="img" aria-hidden="true" focusable="false" height="10" viewBox="0 0 10 10" width="10" xmlns="http://www.w3.org/2000/svg"> <path d="m5.96738168 4.70639573 2.39518594-2.41447274c.37913917-.38219212.98637524-.38972225 1.35419292-.01894278.37750606.38054586.37784436.99719163-.00013556 1.37821513l-4.03074001 4.06319683c-.37758093.38062133-.98937525.38100976-1.367372-.00003075l-4.03091981-4.06337806c-.37759778-.38063832-.38381821-.99150444-.01600053-1.3622839.37750607-.38054587.98772445-.38240057 1.37006824.00302197l2.39538588 2.4146743.96295325.98624457z" fill="#666" fill-rule="evenodd" transform="matrix(0 -1 1 0 0 10)"/> </svg> </li><li class="c-breadcrumbs__item" id="breadcrumb3" itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem"> <span itemprop="name">article</span><meta itemprop="position" content="4"></li> </ol> </div> </nav> </div> <div class="u-container u-mt-32 u-mb-32 u-clearfix" id="content" data-component="article-container" data-container-type="article"> <main class="c-article-main-column u-float-left js-main-column" data-track-component="article body"> <div class="c-context-bar u-hide" data-test="context-bar" data-context-bar aria-hidden="true"> <div class="c-context-bar__container u-container" data-track-context="sticky banner"> <div class="c-context-bar__title"> Seeded X-ray free-electron laser generating radiation with laser statistical properties </div> <div class="c-pdf-download u-clear-both js-pdf-download"> <a href="/articles/s41467-018-06743-8.pdf" class="u-button u-button--full-width u-button--primary u-justify-content-space-between c-pdf-download__link" data-article-pdf="true" data-readcube-pdf-url="true" data-test="download-pdf" data-draft-ignore="true" data-track="content_download" data-track-type="article pdf download" data-track-action="download pdf" data-track-label="link" data-track-external download> <span class="c-pdf-download__text">Download PDF</span> <svg aria-hidden="true" focusable="false" width="16" height="16" class="u-icon"><use xlink:href="#icon-download"/></svg> </a> </div> </div> </div> <article lang="en"> <div class="c-pdf-button__container u-mb-16 u-hide-at-lg js-context-bar-sticky-point-mobile"> <div class="c-pdf-container" data-track-context="article body"> <div class="c-pdf-download u-clear-both js-pdf-download"> <a href="/articles/s41467-018-06743-8.pdf" class="u-button u-button--full-width u-button--primary u-justify-content-space-between c-pdf-download__link" data-article-pdf="true" data-readcube-pdf-url="true" data-test="download-pdf" data-draft-ignore="true" data-track="content_download" data-track-type="article pdf download" data-track-action="download pdf" data-track-label="link" data-track-external download> <span class="c-pdf-download__text">Download PDF</span> <svg aria-hidden="true" focusable="false" width="16" height="16" class="u-icon"><use xlink:href="#icon-download"/></svg> </a> </div> </div> </div> <div class="c-article-header"> <header> <ul class="c-article-identifiers" data-test="article-identifier"> <li class="c-article-identifiers__item" data-test="article-category">Article</li> <li class="c-article-identifiers__item"> <a href="https://www.springernature.com/gp/open-research/about/the-fundamentals-of-open-access-and-open-research" data-track="click" data-track-action="open access" data-track-label="link" class="u-color-open-access" data-test="open-access">Open access</a> </li> <li class="c-article-identifiers__item">Published: <time datetime="2018-10-29">29 October 2018</time></li> </ul> <h1 class="c-article-title" data-test="article-title" data-article-title="">Seeded X-ray free-electron laser generating radiation with laser statistical properties</h1> <ul class="c-article-author-list c-article-author-list--short" data-test="authors-list" data-component-authors-activator="authors-list"><li class="c-article-author-list__item"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Oleg_Yu_-Gorobtsov-Aff1-Aff9" data-author-popup="auth-Oleg_Yu_-Gorobtsov-Aff1-Aff9" data-author-search="Gorobtsov, Oleg Yu.">Oleg Yu. Gorobtsov</a><sup class="u-js-hide"><a href="#Aff1">1</a>,<a href="#Aff9">9</a></sup><sup class="u-js-hide"> <a href="#nAff2">nAff2</a></sup>, </li><li class="c-article-author-list__item"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Giuseppe-Mercurio-Aff2-Aff10" data-author-popup="auth-Giuseppe-Mercurio-Aff2-Aff10" data-author-search="Mercurio, Giuseppe">Giuseppe Mercurio</a><sup class="u-js-hide"><a href="#Aff2">2</a>,<a href="#Aff10">10</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Flavio-Capotondi-Aff3" data-author-popup="auth-Flavio-Capotondi-Aff3" data-author-search="Capotondi, Flavio">Flavio Capotondi</a><sup class="u-js-hide"><a href="#Aff3">3</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Petr-Skopintsev-Aff1-Aff11" data-author-popup="auth-Petr-Skopintsev-Aff1-Aff11" data-author-search="Skopintsev, Petr">Petr Skopintsev</a><sup class="u-js-hide"><a href="#Aff1">1</a>,<a href="#Aff11">11</a></sup><sup class="u-js-hide"> <a href="#nAff5">nAff5</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Sergey-Lazarev-Aff1-Aff4" data-author-popup="auth-Sergey-Lazarev-Aff1-Aff4" data-author-search="Lazarev, Sergey">Sergey Lazarev</a><span class="u-js-hide"> <a class="js-orcid" href="http://orcid.org/0000-0002-7230-3559"><span class="u-visually-hidden">ORCID: </span>orcid.org/0000-0002-7230-3559</a></span><sup class="u-js-hide"><a href="#Aff1">1</a>,<a href="#Aff4">4</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Ivan_A_-Zaluzhnyy-Aff1-Aff5-Aff12" data-author-popup="auth-Ivan_A_-Zaluzhnyy-Aff1-Aff5-Aff12" data-author-search="Zaluzhnyy, Ivan A.">Ivan A. Zaluzhnyy</a><span class="u-js-hide"> <a class="js-orcid" href="http://orcid.org/0000-0001-5946-2777"><span class="u-visually-hidden">ORCID: </span>orcid.org/0000-0001-5946-2777</a></span><sup class="u-js-hide"><a href="#Aff1">1</a>,<a href="#Aff5">5</a>,<a href="#Aff12">12</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Miltcho_B_-Danailov-Aff3" data-author-popup="auth-Miltcho_B_-Danailov-Aff3" data-author-search="Danailov, Miltcho B.">Miltcho B. Danailov</a><sup class="u-js-hide"><a href="#Aff3">3</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Martina-Dell_Angela-Aff6" data-author-popup="auth-Martina-Dell_Angela-Aff6" data-author-search="Dell’Angela, Martina">Martina Dell’Angela</a><sup class="u-js-hide"><a href="#Aff6">6</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Michele-Manfredda-Aff3" data-author-popup="auth-Michele-Manfredda-Aff3" data-author-search="Manfredda, Michele">Michele Manfredda</a><sup class="u-js-hide"><a href="#Aff3">3</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Emanuele-Pedersoli-Aff3" data-author-popup="auth-Emanuele-Pedersoli-Aff3" data-author-search="Pedersoli, Emanuele">Emanuele Pedersoli</a><span class="u-js-hide"> <a class="js-orcid" href="http://orcid.org/0000-0003-0572-6735"><span class="u-visually-hidden">ORCID: </span>orcid.org/0000-0003-0572-6735</a></span><sup class="u-js-hide"><a href="#Aff3">3</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Luca-Giannessi-Aff3-Aff7" data-author-popup="auth-Luca-Giannessi-Aff3-Aff7" data-author-search="Giannessi, Luca">Luca Giannessi</a><sup class="u-js-hide"><a href="#Aff3">3</a>,<a href="#Aff7">7</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Maya-Kiskinova-Aff3" data-author-popup="auth-Maya-Kiskinova-Aff3" data-author-search="Kiskinova, Maya">Maya Kiskinova</a><span class="u-js-hide"> <a class="js-orcid" href="http://orcid.org/0000-0001-9584-3526"><span class="u-visually-hidden">ORCID: </span>orcid.org/0000-0001-9584-3526</a></span><sup class="u-js-hide"><a href="#Aff3">3</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Kevin_C_-Prince-Aff3-Aff8" data-author-popup="auth-Kevin_C_-Prince-Aff3-Aff8" data-author-search="Prince, Kevin C.">Kevin C. Prince</a><span class="u-js-hide"> <a class="js-orcid" href="http://orcid.org/0000-0002-5416-7354"><span class="u-visually-hidden">ORCID: </span>orcid.org/0000-0002-5416-7354</a></span><sup class="u-js-hide"><a href="#Aff3">3</a>,<a href="#Aff8">8</a></sup>, </li><li class="c-article-author-list__item c-article-author-list__item--hide-small-screen"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Wilfried-Wurth-Aff1-Aff2" data-author-popup="auth-Wilfried-Wurth-Aff1-Aff2" data-author-search="Wurth, Wilfried">Wilfried Wurth</a><sup class="u-js-hide"><a href="#Aff1">1</a>,<a href="#Aff2">2</a></sup> & </li><li class="c-article-author-list__show-more" aria-label="Show all 15 authors for this article" title="Show all 15 authors for this article">…</li><li class="c-article-author-list__item"><a data-test="author-name" data-track="click" data-track-action="open author" data-track-label="link" href="#auth-Ivan_A_-Vartanyants-Aff1-Aff5" data-author-popup="auth-Ivan_A_-Vartanyants-Aff1-Aff5" data-author-search="Vartanyants, Ivan A." data-corresp-id="c1">Ivan A. Vartanyants<svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-mail-medium"></use></svg></a><span class="u-js-hide"> <a class="js-orcid" href="http://orcid.org/0000-0002-0340-8234"><span class="u-visually-hidden">ORCID: </span>orcid.org/0000-0002-0340-8234</a></span><sup class="u-js-hide"><a href="#Aff1">1</a>,<a href="#Aff5">5</a></sup> </li></ul><button aria-expanded="false" class="c-article-author-list__button"><svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-chevron-down-medium"></use></svg><span>Show authors</span></button> <p class="c-article-info-details" data-container-section="info"> <a data-test="journal-link" href="/ncomms" data-track="click" data-track-action="journal homepage" data-track-category="article body" data-track-label="link"><i data-test="journal-title">Nature Communications</i></a> <b data-test="journal-volume"><span class="u-visually-hidden">volume</span> 9</b>, Article number: <span data-test="article-number">4498</span> (<span data-test="article-publication-year">2018</span>) <a href="#citeas" class="c-article-info-details__cite-as u-hide-print" data-track="click" data-track-action="cite this article" data-track-label="link">Cite this article</a> </p> <div class="c-article-metrics-bar__wrapper u-clear-both"> <ul class="c-article-metrics-bar u-list-reset"> <li class=" c-article-metrics-bar__item" data-test="access-count"> <p class="c-article-metrics-bar__count">4002 <span class="c-article-metrics-bar__label">Accesses</span></p> </li> <li class="c-article-metrics-bar__item" data-test="citation-count"> <p class="c-article-metrics-bar__count">53 <span class="c-article-metrics-bar__label">Citations</span></p> </li> <li class="c-article-metrics-bar__item" data-test="altmetric-score"> <p class="c-article-metrics-bar__count">3 <span class="c-article-metrics-bar__label">Altmetric</span></p> </li> <li class="c-article-metrics-bar__item"> <p class="c-article-metrics-bar__details"><a href="/articles/s41467-018-06743-8/metrics" data-track="click" data-track-action="view metrics" data-track-label="link" rel="nofollow">Metrics <span class="u-visually-hidden">details</span></a></p> </li> </ul> </div> </header> <div class="u-js-hide" data-component="article-subject-links"> <h3 class="c-article__sub-heading">Subjects</h3> <ul class="c-article-subject-list"> <li class="c-article-subject-list__subject"><a href="/subjects/free-electron-lasers" data-track="click" data-track-action="view subject" data-track-label="link">Free-electron lasers</a></li><li class="c-article-subject-list__subject"><a href="/subjects/spectroscopy" data-track="click" data-track-action="view subject" data-track-label="link">Optical spectroscopy</a></li> </ul> </div> <div class="u-mb-8 c-status-message c-status-message--boxed c-status-message--info"> <span class="c-status-message__icon"> <svg class="u-icon" width="18" height="18" aria-hidden="true" focusable="false"> <use xlink:href="#icon-eds-i-info-filled-medium"></use> </svg> </span> <p class="u-mt-0">A <a href="https://doi.org/10.1038/s41467-019-13249-4" class="relation-link" data-track="click" data-track-action="view linked article" data-track-label="link">Publisher Correction</a> to this article was published on 13 November 2019</p> </div> <div class="u-mb-8 c-status-message c-status-message--boxed c-status-message--info"> <span class="c-status-message__icon"> <svg class="u-icon" width="18" height="18" aria-hidden="true" focusable="false"> <use xlink:href="#icon-eds-i-info-filled-medium"></use> </svg> </span> <p class="u-mt-0">This article has been <a href="#change-history">updated</a></p> </div> </div> <div class="c-article-body"> <section aria-labelledby="Abs1" data-title="Abstract" lang="en"><div class="c-article-section" id="Abs1-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Abs1">Abstract</h2><div class="c-article-section__content" id="Abs1-content"><p>The invention of optical lasers led to a revolution in the field of optics and to the creation of such fields of research as quantum optics. The reason was their unique statistical and coherence properties. The emerging, short-wavelength free-electron lasers (FELs) are sources of very bright coherent extreme-ultraviolet and X-ray radiation with pulse durations on the order of femtoseconds, and are presently considered to be laser sources at these energies. FELs are highly spatially coherent to the first-order but in spite of their name, behave statistically as chaotic sources. Here, we demonstrate experimentally, by combining Hanbury Brown and Twiss interferometry with spectral measurements that the seeded XUV FERMI FEL-2 source does indeed behave statistically as a laser. The results may be useful for quantum optics experiments and for the design and operation of next generation FEL sources.</p></div></div></section> <section aria-labelledby="inline-recommendations" data-title="Inline Recommendations" class="c-article-recommendations" data-track-component="inline-recommendations"> <h3 class="c-article-recommendations-title" id="inline-recommendations">Similar content being viewed by others</h3> <div class="c-article-recommendations-list"> <div class="c-article-recommendations-list__item"> <article class="c-article-recommendations-card" itemscope itemtype="http://schema.org/ScholarlyArticle"> <div class="c-article-recommendations-card__img"><img src="https://media.springernature.com/w215h120/springer-static/image/art%3A10.1038%2Fs41566-022-01104-w/MediaObjects/41566_2022_1104_Fig1_HTML.png" loading="lazy" alt=""></div> <div class="c-article-recommendations-card__main"> <h3 class="c-article-recommendations-card__heading" itemprop="name headline"> <a class="c-article-recommendations-card__link" itemprop="url" href="https://www.nature.com/articles/s41566-022-01104-w?fromPaywallRec=false" data-track="select_recommendations_1" data-track-context="inline recommendations" data-track-action="click recommendations inline - 1" data-track-label="10.1038/s41566-022-01104-w">Seeded free-electron laser driven by a compact laser plasma accelerator </a> </h3> <div class="c-article-meta-recommendations" data-test="recommendation-info"> <span class="c-article-meta-recommendations__item-type">Article</span> <span class="c-article-meta-recommendations__access-type">Open access</span> <span class="c-article-meta-recommendations__date">05 December 2022</span> </div> </div> </article> </div> <div class="c-article-recommendations-list__item"> <article class="c-article-recommendations-card" itemscope itemtype="http://schema.org/ScholarlyArticle"> <div class="c-article-recommendations-card__img"><img src="https://media.springernature.com/w215h120/springer-static/image/art%3A10.1038%2Fs41586-024-08209-y/MediaObjects/41586_2024_8209_Fig1_HTML.png" loading="lazy" alt=""></div> <div class="c-article-recommendations-card__main"> <h3 class="c-article-recommendations-card__heading" itemprop="name headline"> <a class="c-article-recommendations-card__link" itemprop="url" href="https://www.nature.com/articles/s41586-024-08209-y?fromPaywallRec=false" data-track="select_recommendations_2" data-track-context="inline recommendations" data-track-action="click recommendations inline - 2" data-track-label="10.1038/s41586-024-08209-y">Strong-field quantum control in the extreme ultraviolet domain using pulse shaping </a> </h3> <div class="c-article-meta-recommendations" data-test="recommendation-info"> <span class="c-article-meta-recommendations__item-type">Article</span> <span class="c-article-meta-recommendations__access-type">Open access</span> <span class="c-article-meta-recommendations__date">11 December 2024</span> </div> </div> </article> </div> <div class="c-article-recommendations-list__item"> <article class="c-article-recommendations-card" itemscope itemtype="http://schema.org/ScholarlyArticle"> <div class="c-article-recommendations-card__img"><img src="https://media.springernature.com/w215h120/springer-static/image/art%3A10.1038%2Fs42005-024-01836-x/MediaObjects/42005_2024_1836_Fig1_HTML.png" loading="lazy" alt=""></div> <div class="c-article-recommendations-card__main"> <h3 class="c-article-recommendations-card__heading" itemprop="name headline"> <a class="c-article-recommendations-card__link" itemprop="url" href="https://www.nature.com/articles/s42005-024-01836-x?fromPaywallRec=false" data-track="select_recommendations_3" data-track-context="inline recommendations" data-track-action="click recommendations inline - 3" data-track-label="10.1038/s42005-024-01836-x">Above-threshold ionization with X-ray free-electron lasers </a> </h3> <div class="c-article-meta-recommendations" data-test="recommendation-info"> <span class="c-article-meta-recommendations__item-type">Article</span> <span class="c-article-meta-recommendations__access-type">Open access</span> <span class="c-article-meta-recommendations__date">28 October 2024</span> </div> </div> </article> </div> </div> </section> <script> window.dataLayer = window.dataLayer || []; window.dataLayer.push({ recommendations: { recommender: 'semantic', model: 'specter', policy_id: 'NA', timestamp: 1740935478, embedded_user: 'null' } }); </script> <div class="main-content"> <section data-title="Introduction"><div class="c-article-section" id="Sec1-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Sec1">Introduction</h2><div class="c-article-section__content" id="Sec1-content"><p>Glauber in his pioneering work<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 1" title="Glauber, R. J. The quantum theory of optical coherence. Phys. Rev. 130, 2529–2539 (1963)." href="/articles/s41467-018-06743-8#ref-CR1" id="ref-link-section-d141568212e786">1</a></sup> stated that a truly coherent source of radiation should be coherent in all orders of intensity correlation functions. Most sources of radiation in the optical wavelength range behave statistically as thermal or chaotic sources. Optical lasers, due to their significantly different radiation properties, provide unique opportunities in science and technology. As first demonstrated in the time domain, single-mode or phase-locked optical lasers are not only coherent in the first-order, but also in the second-order of intensity correlation functions<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 2" title="Arecchi, F. T., Gatti, E. & Sona, A. Time distribution of photons from coherent and Gaussian sources. Phys. Lett. 20, 27–29 (1966)." href="/articles/s41467-018-06743-8#ref-CR2" id="ref-link-section-d141568212e790">2</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 3" title="Loudon, R. The Quantum Theory of Light. 3rd edn, (Oxford University Press, Great Britain, 2000)." href="/articles/s41467-018-06743-8#ref-CR3" id="ref-link-section-d141568212e793">3</a></sup>. This is also valid in the spatial domain and distinguishes laser sources from chaotic sources of radiation. This difference is especially important for quantum optics experiments that are extended now to classical fields<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 4" title="Oppel, S., Wiegner, R., Agarwal, G. S. & von Zanthier, J. Directional superradiant emission from statistically independent incoherent nonclassical and classical sources. Phys. Rev. Lett. 113, 263606 (2014)." href="/articles/s41467-018-06743-8#ref-CR4" id="ref-link-section-d141568212e797">4</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 5" title="Schneider, R. et al. Quantum imaging with incoherently scattered light from a free-electron laser. Nat. Phys. 14, 126–129 (2018)." href="/articles/s41467-018-06743-8#ref-CR5" id="ref-link-section-d141568212e800">5</a></sup>, in which high-order coherence properties of the source play an important role. The possibility of employing similar properties of sources in the extreme-ultraviolet (XUV) and X-ray range with extremely high brightness is the main attraction for completely new and exciting applications of free-electron lasers (FELs).</p><p>Most of the presently operating short-wavelength FELs<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Ackermann, W. et al. Operation of a free-electron laser from the extreme ultraviolet to the water window. Nat. Photon. 1, 336–342 (2007)." href="#ref-CR6" id="ref-link-section-d141568212e807">6</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Allaria, E. et al. Two-stage seeded soft-X-ray free-electron laser. Nat. Photon. 7, 913–918 (2013)." href="#ref-CR7" id="ref-link-section-d141568212e807_1">7</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Emma, P. et al. First lasing and operation of an ångstrom-wavelength free-electron laser. Nat. Photon. 4, 641–647 (2010)." href="#ref-CR8" id="ref-link-section-d141568212e807_2">8</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Ishikawa, T. et al. A compact x-ray free-electron laser emitting in the sub-angstrom region. Nat. Photon. 6, 540–544 (2012)." href="#ref-CR9" id="ref-link-section-d141568212e807_3">9</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 10" title="Altarelli, M. et al. The European X-ray Free-electron Laser—technical Design Report. Technical Report DESY 2006-097. European XFEL Project Team (Deutsches Elektronen-Synchrotron, Hamburg, 2006)." href="/articles/s41467-018-06743-8#ref-CR10" id="ref-link-section-d141568212e810">10</a></sup> generate radiation using the self-amplified spontaneous emission (SASE) process<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 11" title="Saldin, E., Schneidmiller, E. & Yurkov, M. The Physics of Free Electron Laser. (Springer-Verlag, Berlin, 2000)." href="/articles/s41467-018-06743-8#ref-CR11" id="ref-link-section-d141568212e814">11</a></sup>, where the radiation is produced stochastically by the electron bunch shot noise. As a result, the spatial and especially temporal structure of the X-ray pulse fluctuates strongly from shot to shot. Typically, each SASE pulse contains a large number of longitudinal modes without any phase locking between them. As such, SASE FELs are spatially highly coherent sources in first-order (with the degree of spatial coherence reaching 80%<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 12" title="Vartanyants, I. A. et al. Coherence properties of individual femtosecond pulses of an x-ray free-electron laser. Phys. Rev. Lett. 107, 144801 (2011)." href="/articles/s41467-018-06743-8#ref-CR12" id="ref-link-section-d141568212e818">12</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 13" title="Singer, A. et al. Spatial and temporal coherence properties of single free-electron laser pulses. Opt. Express 20, 17480–17495 (2012)." href="/articles/s41467-018-06743-8#ref-CR13" id="ref-link-section-d141568212e821">13</a></sup>), but from a statistical point of view, they behave as chaotic sources of radiation<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Singer, A. et al. Hanbury Brown-Twiss interferometry at a free-electron laser. Phys. Rev. Lett. 111, 034802 (2013). Erratum: 117, 239903(E) (2016)." href="#ref-CR14" id="ref-link-section-d141568212e825">14</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Gorobtsov, O. Yu et al. Statistical properties of a free-electron laser revealed by Hanbury Brown-Twiss interferometry. Phys. Rev. A 95, 023843 (2017)." href="#ref-CR15" id="ref-link-section-d141568212e825_1">15</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 16" title="Gorobtsov, O. Yu et al. Diffraction based Hanbury Brown and Twiss interferometry performed at a hard x-ray free-electron laser. Sci. Rep. 8, 2219 (2018)." href="/articles/s41467-018-06743-8#ref-CR16" id="ref-link-section-d141568212e828">16</a></sup>. The first steps have been taken towards exploiting the first-order coherence of FELs<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 17" title="Prince, K. C. et al. Coherent control with a short-wavelength free-electron laser. Nat. Photon. 10, 176–179 (2016)." href="/articles/s41467-018-06743-8#ref-CR17" id="ref-link-section-d141568212e832">17</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 18" title="Usenko, S. et al. Attosecond interferometry with self-amplified spontaneous emission of a free-electron laser. Nat. Commun. 8, 15626 (2017)." href="/articles/s41467-018-06743-8#ref-CR18" id="ref-link-section-d141568212e835">18</a></sup>, but to date, no consistent high-order statistical measurements have been performed at any seeded FEL.</p><p>FERMI is the first seeded single-pass FEL in the XUV regime and hosts two sources<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 7" title="Allaria, E. et al. Two-stage seeded soft-X-ray free-electron laser. Nat. Photon. 7, 913–918 (2013)." href="/articles/s41467-018-06743-8#ref-CR7" id="ref-link-section-d141568212e842">7</a></sup> FEL-1 and FEL-2. Recent measurements have demonstrated that FERMI FEL-1 is coherent in the temporal domain<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 19" title="De Ninno, G. et al. Single-shot spectro-temporal characterization of XUV pulses from a seeded free-electron laser. Nat. Commun. 6, 8075 (2015)." href="/articles/s41467-018-06743-8#ref-CR19" id="ref-link-section-d141568212e846">19</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 20" title="Gauthier, D. et al. Spectrotemporal shaping of seeded free-electron laser pulses. Phys. Rev. Lett. 115, 114801 (2015)." href="/articles/s41467-018-06743-8#ref-CR20" id="ref-link-section-d141568212e849">20</a></sup>. The question naturally arises whether this indicates only first-order coherence, or whether the FERMI FEL is also coherent in higher orders, thus satisfying the definition of Glauber. This is an important question, as it defines the potential of this light source for experiments based on high-order intensity correlations, a common requirement for quantum optics investigations<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 3" title="Loudon, R. The Quantum Theory of Light. 3rd edn, (Oxford University Press, Great Britain, 2000)." href="/articles/s41467-018-06743-8#ref-CR3" id="ref-link-section-d141568212e853">3</a></sup>.</p><p>Here we employ Hanbury Brown and Twiss (HBT) interferometry to explore the statistical properties of radiation from a FEL source. We perform the higher-order intensity correlation measurements at FERMI and demonstrate that it statistically behaves as a laser source.</p></div></div></section><section data-title="Results"><div class="c-article-section" id="Sec2-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Sec2">Results</h2><div class="c-article-section__content" id="Sec2-content"><h3 class="c-article__sub-heading" id="Sec3">HBT correlation and spectral analysis</h3><p>The basic idea behind HBT interferometry<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 21" title="Hanbury Brown, R. & Twiss, R. Q. Correlation between photons in two coherent beams of light. Nature 177, 27–32 (1956)." href="/articles/s41467-018-06743-8#ref-CR21" id="ref-link-section-d141568212e872">21</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 22" title="Hanbury Brown, R. & Twiss, R. Q. A test of a new type of stellar interferometer on Sirius. Nature 178, 1046–1048 (1956)." href="/articles/s41467-018-06743-8#ref-CR22" id="ref-link-section-d141568212e875">22</a></sup> is to extract statistical properties of radiation from the normalised second-order intensity correlation function<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 23" title="Paul, H. Interference between independent photons. Rev. Mod. Phys. 58, 209–231 (1986)." href="/articles/s41467-018-06743-8#ref-CR23" id="ref-link-section-d141568212e879">23</a></sup></p><div id="Equ1" class="c-article-equation"><div class="c-article-equation__content"><span class="mathjax-tex">$$g^{\left( 2 \right)}\left( {{\boldsymbol{r}}_1,{\bf{r}}_2} \right) = \left\langle {I\left( {{\bf{r}}_1} \right)I\left( {{\bf{r}}_2} \right)} \right\rangle {\mathrm{/}}\left\langle {I\left( {{\bf{r}}_1} \right)} \right\rangle \left\langle {I\left( {{\bf{r}}_2} \right)} \right\rangle ,$$</span></div><div class="c-article-equation__number"> (1) </div></div><p>where <i>I</i>(<b>r</b><sub><b>1</b></sub>) and <i>I</i>(<b>r</b><sub><b>2</b></sub>) are intensities at different spatial positions measured simultaneously, and the brackets <span class="mathjax-tex">$\left\langle \ldots \right\rangle$</span> denote averaging over a large ensemble of different radiation pulses. The statistical behaviour of the <i>g</i><sup>(2)</sup> correlation function is fundamental in quantum optics<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 3" title="Loudon, R. The Quantum Theory of Light. 3rd edn, (Oxford University Press, Great Britain, 2000)." href="/articles/s41467-018-06743-8#ref-CR3" id="ref-link-section-d141568212e993">3</a></sup> and strongly depends on the radiation type. For example, for coherent laser sources <i>g</i><sup>(2)</sup> is equal to one<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 2" title="Arecchi, F. T., Gatti, E. & Sona, A. Time distribution of photons from coherent and Gaussian sources. Phys. Lett. 20, 27–29 (1966)." href="/articles/s41467-018-06743-8#ref-CR2" id="ref-link-section-d141568212e1002">2</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 3" title="Loudon, R. The Quantum Theory of Light. 3rd edn, (Oxford University Press, Great Britain, 2000)." href="/articles/s41467-018-06743-8#ref-CR3" id="ref-link-section-d141568212e1005">3</a></sup> but for chaotic sources it behaves quite differently (see Methods Eq. (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ4">4</a>)).</p><p>Measurements were performed at the DiProI end-station of FERMI using the FEL-2 source and acquiring simultaneously data from the on-line spectrometer PRESTO (see Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig1">1</a>, Experimental details, and Supplementary Note <a data-track="click" data-track-label="link" data-track-action="supplementary material anchor" href="/articles/s41467-018-06743-8#MOESM1">1</a>). This feature of FERMI allowed us to analyse simultaneously the spectral and intensity profiles of each pulse delivered and measured at the DiProI end-station. One more important feature of FERMI is that its operation can be switched from seeded to SASE mode<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 24" title="Penco, G. et al. Optical Klystron enhancement to self amplified spontaneous emission at FERMI. Photonics 4, 15 (2017)." href="/articles/s41467-018-06743-8#ref-CR24" id="ref-link-section-d141568212e1021">24</a></sup>.</p><div class="c-article-section__figure js-c-reading-companion-figures-item" data-test="figure" data-container-section="figure" id="figure-1" data-title="Fig. 1"><figure><figcaption><b id="Fig1" class="c-article-section__figure-caption" data-test="figure-caption-text">Fig. 1</b></figcaption><div class="c-article-section__figure-content"><div class="c-article-section__figure-item"><a class="c-article-section__figure-link" data-test="img-link" data-track="click" data-track-label="image" data-track-action="view figure" href="/articles/s41467-018-06743-8/figures/1" rel="nofollow"><picture><source type="image/webp" srcset="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig1_HTML.png?as=webp"><img aria-describedby="Fig1" src="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig1_HTML.png" alt="figure 1" loading="lazy" width="685" height="209"></picture></a></div><div class="c-article-section__figure-description" data-test="bottom-caption" id="figure-1-desc"><p>Schematic layout of the experiment. Radiation generated in the undulators is focused by Kirkpatrick–Baez mirrors and the detector is installed out of focus to observe the direct beam. Radiation from each pulse is partially diffracted by a grating to the spectrometer detector to observe on-line pulse spectra</p></div></div><div class="u-text-right u-hide-print"><a class="c-article__pill-button" data-test="article-link" data-track="click" data-track-label="button" data-track-action="view figure" href="/articles/s41467-018-06743-8/figures/1" data-track-dest="link:Figure1 Full size image" aria-label="Full size image figure 1" rel="nofollow"><span>Full size image</span><svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-chevron-right-small"></use></svg></a></div></figure></div><p>We first analysed the X-ray intensity distribution of the FEL pulses in the seeded and SASE regimes of FERMI FEL-2 by employing HBT correlation analysis (Eq. (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ1">1</a>)). Intensity correlation functions measured in the vertical and horizontal directions for both operation modes are shown in Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig2">2a–d</a>. The contrast values of the intensity correlation function (see Methods Eq. (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ3">3</a>)) in the central part of the beam were on the order of 0.03–0.04 for the seeded beam and slightly higher about 0.1–0.15 for the SASE. The remarkable difference between the two regimes of operation becomes evident by correlating these observations to the corresponding spectral profiles.</p><div class="c-article-section__figure js-c-reading-companion-figures-item" data-test="figure" data-container-section="figure" id="figure-2" data-title="Fig. 2"><figure><figcaption><b id="Fig2" class="c-article-section__figure-caption" data-test="figure-caption-text">Fig. 2</b></figcaption><div class="c-article-section__figure-content"><div class="c-article-section__figure-item"><a class="c-article-section__figure-link" data-test="img-link" data-track="click" data-track-label="image" data-track-action="view figure" href="/articles/s41467-018-06743-8/figures/2" rel="nofollow"><picture><source type="image/webp" srcset="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig2_HTML.png?as=webp"><img aria-describedby="Fig2" src="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig2_HTML.png" alt="figure 2" loading="lazy" width="685" height="880"></picture></a></div><div class="c-article-section__figure-description" data-test="bottom-caption" id="figure-2-desc"><p>Correlation functions and spectra measured in different modes of operation. <b>a</b>–<b>d</b> Intensity correlation functions for seeded (<b>a</b>, <b>c</b>) and self-amplified spontaneous emission (SASE) (<b>b</b>, <b>d</b>) regimes of operation in vertical (<b>a</b>, <b>b</b>) and horizontal (<b>c</b>, <b>d</b>) directions. Spectral structure of an individual pulse (blue line), average spectrum (black line) and Gaussian fit (red dashed line) for seeded (<b>e</b>) and SASE (<b>f</b>) regimes of operation</p></div></div><div class="u-text-right u-hide-print"><a class="c-article__pill-button" data-test="article-link" data-track="click" data-track-label="button" data-track-action="view figure" href="/articles/s41467-018-06743-8/figures/2" data-track-dest="link:Figure2 Full size image" aria-label="Full size image figure 2" rel="nofollow"><span>Full size image</span><svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-chevron-right-small"></use></svg></a></div></figure></div><p>The average spectrum, both in the seeded and SASE regimes of FERMI operation, was approximately Gaussian in shape but with a quite different relative bandwidth Δ<i>ω</i>/<i>ω</i><sub>0</sub> (see Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig2">2e, f</a>). In the seeded regime it was about 4.6 × 10<sup>−4</sup> and in SASE 6 × 10<sup>−3</sup>, an order of magnitude broader. The low values of the contrast measured in the seeded regime, in the case of a chaotic Gaussian beam, would indicate the presence of at least 25–30 independent longitudinal modes<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Singer, A. et al. Hanbury Brown-Twiss interferometry at a free-electron laser. Phys. Rev. Lett. 111, 034802 (2013). Erratum: 117, 239903(E) (2016)." href="#ref-CR14" id="ref-link-section-d141568212e1108">14</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" title="Gorobtsov, O. Yu et al. Statistical properties of a free-electron laser revealed by Hanbury Brown-Twiss interferometry. Phys. Rev. A 95, 023843 (2017)." href="#ref-CR15" id="ref-link-section-d141568212e1108_1">15</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 16" title="Gorobtsov, O. Yu et al. Diffraction based Hanbury Brown and Twiss interferometry performed at a hard x-ray free-electron laser. Sci. Rep. 8, 2219 (2018)." href="/articles/s41467-018-06743-8#ref-CR16" id="ref-link-section-d141568212e1111">16</a></sup>. However, from our on-line spectrometer measurements, we observed from one to five modes varying from pulse to pulse, with one mode usually dominating. At the same time, the values of contrast obtained in SASE mode match the number of observed spectral modes (about 10), supporting the assumption of chaotic character of the source in the SASE regime (see Methods Eq. (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ4">4</a>)).</p><p>Next, we proceeded with analysis of the spectral dependence of the <i>g</i><sup>(2)</sup> function in the seeded regime of FERMI operation by implementing a sorting procedure (see Supplementary Note <a data-track="click" data-track-label="link" data-track-action="supplementary material anchor" href="/articles/s41467-018-06743-8#MOESM1">2</a>). Two data sets of pulses were then considered: 10<sup>3</sup> pulses with the largest contribution of the main mode and 10<sup>3</sup> pulses with the smallest contribution. Intensity correlation functions determined by Eq. (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ1">1</a>) for these two data sets are presented in Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig3">3a, c</a> and examples of the single and multimode pulses are shown in Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig3">3b, d</a>. Remarkably, these two data sets produce similar correlation functions with low values of contrast of about 0.02 and 0.07 for the data set with the smallest and largest contribution of the main mode, respectively. Based on these results, we conclude that the seeded FERMI FEL-2 source is not behaving as a chaotic source but rather as a laser source, even in the case when several modes are present in the spectrum. This implies that the spectral modes are potentially phase locked, as in the case of FERMI FEL-1<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 19" title="De Ninno, G. et al. Single-shot spectro-temporal characterization of XUV pulses from a seeded free-electron laser. Nat. Commun. 6, 8075 (2015)." href="/articles/s41467-018-06743-8#ref-CR19" id="ref-link-section-d141568212e1143">19</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 20" title="Gauthier, D. et al. Spectrotemporal shaping of seeded free-electron laser pulses. Phys. Rev. Lett. 115, 114801 (2015)." href="/articles/s41467-018-06743-8#ref-CR20" id="ref-link-section-d141568212e1146">20</a></sup>, which is an important finding for coherent control experiments<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 17" title="Prince, K. C. et al. Coherent control with a short-wavelength free-electron laser. Nat. Photon. 10, 176–179 (2016)." href="/articles/s41467-018-06743-8#ref-CR17" id="ref-link-section-d141568212e1150">17</a></sup>.</p><div class="c-article-section__figure js-c-reading-companion-figures-item" data-test="figure" data-container-section="figure" id="figure-3" data-title="Fig. 3"><figure><figcaption><b id="Fig3" class="c-article-section__figure-caption" data-test="figure-caption-text">Fig. 3</b></figcaption><div class="c-article-section__figure-content"><div class="c-article-section__figure-item"><a class="c-article-section__figure-link" data-test="img-link" data-track="click" data-track-label="image" data-track-action="view figure" href="/articles/s41467-018-06743-8/figures/3" rel="nofollow"><picture><source type="image/webp" srcset="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig3_HTML.png?as=webp"><img aria-describedby="Fig3" src="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig3_HTML.png" alt="figure 3" loading="lazy" width="685" height="519"></picture></a></div><div class="c-article-section__figure-description" data-test="bottom-caption" id="figure-3-desc"><p>Seeded mode single and multiple pulses analysis. Intensity correlation functions (<b>a</b>, <b>c</b>) and spectral structure (<b>b</b>, <b>d</b>) for the sorted pulses with the lowest (<b>a</b>, <b>b</b>) and highest (<b>c</b>, <b>d</b>) number of modes. In (<b>b</b>, <b>d</b>) representative single pulses are shown by blue lines, an average over 10<sup>3</sup> pulses is shown by black lines, and Gaussian fit by red dashed lines. Note the different scale in frequency <i>ω</i> in comparison with Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig2">2b, d</a></p></div></div><div class="u-text-right u-hide-print"><a class="c-article__pill-button" data-test="article-link" data-track="click" data-track-label="button" data-track-action="view figure" href="/articles/s41467-018-06743-8/figures/3" data-track-dest="link:Figure3 Full size image" aria-label="Full size image figure 3" rel="nofollow"><span>Full size image</span><svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-chevron-right-small"></use></svg></a></div></figure></div><h3 class="c-article__sub-heading" id="Sec4">Probability distribution and dispersion values of intensity</h3><p>To further investigate the difference between the seeded and SASE operation modes, the probability distribution of total intensity was studied in both cases (see Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig4">4a, c</a>). As known from the first-order coherence theory, there is little difference between a multimode laser without phase locking and a chaotic source<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 25" title="Goodman, J. W. Statistical Optics. (Wiley, Hoboken, NJ, 2000)." href="/articles/s41467-018-06743-8#ref-CR25" id="ref-link-section-d141568212e1212">25</a></sup>. In both cases the total pulse intensity distribution follows a Gamma distribution. We indeed observed such behaviour in the SASE regime of FERMI with about eight longitudinal modes (see Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig4">4c</a>). At the same time, in the seeded mode, fitting data with a Gamma distribution does not well represent the measured distribution and gives the unlikely result of 58 modes (see Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig4">4a</a>), contradicting the spectral observation. A much better fit was provided by a Gaussian density function, with a number of modes close to one<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 25" title="Goodman, J. W. Statistical Optics. (Wiley, Hoboken, NJ, 2000)." href="/articles/s41467-018-06743-8#ref-CR25" id="ref-link-section-d141568212e1222">25</a></sup> (see Methods Eqs. (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ5">5</a>) and (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ6">6</a>)). This is also consistent with the statistical behaviour of the FERMI FEL-2 source conforming to that of a phase-locked laser.</p><div class="c-article-section__figure js-c-reading-companion-figures-item" data-test="figure" data-container-section="figure" id="figure-4" data-title="Fig. 4"><figure><figcaption><b id="Fig4" class="c-article-section__figure-caption" data-test="figure-caption-text">Fig. 4</b></figcaption><div class="c-article-section__figure-content"><div class="c-article-section__figure-item"><a class="c-article-section__figure-link" data-test="img-link" data-track="click" data-track-label="image" data-track-action="view figure" href="/articles/s41467-018-06743-8/figures/4" rel="nofollow"><picture><source type="image/webp" srcset="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig4_HTML.png?as=webp"><img aria-describedby="Fig4" src="//media.springernature.com/lw685/springer-static/image/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_Fig4_HTML.png" alt="figure 4" loading="lazy" width="685" height="412"></picture></a></div><div class="c-article-section__figure-description" data-test="bottom-caption" id="figure-4-desc"><p>Histograms and dispersion values of intensity in different modes of operation. <b>a</b>, <b>c</b> Histograms of probability distributions of intensity, p(I/〈I〉), for seeded (<b>a</b>) and self-amplified spontaneous emission (SASE) (<b>c</b>) regimes. The red line represents a fit by a Gamma function and the black line represents a fit by a Gaussian function. Number of modes determined from the Gamma distribution is indicated by <i>M</i>. (<b>b</b>, <b>d</b>) Contrast behaviour as a function of inverse bandwidth for seeded (<b>b</b>) and SASE (<b>d</b>) regimes of operation</p></div></div><div class="u-text-right u-hide-print"><a class="c-article__pill-button" data-test="article-link" data-track="click" data-track-label="button" data-track-action="view figure" href="/articles/s41467-018-06743-8/figures/4" data-track-dest="link:Figure4 Full size image" aria-label="Full size image figure 4" rel="nofollow"><span>Full size image</span><svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-chevron-right-small"></use></svg></a></div></figure></div><p>We also analysed the dispersion values of the total intensity <i>I</i> given by <i>ζ</i><sub>tot</sub> = 〈<i>δI</i><sup>2</sup>〉/〈<i>I</i>〉<sup>2</sup>, where <i>δI</i> = <i>I</i> − 〈<i>I</i>〉. They were measured at the spectrometer as a function of the radiation bandwidth for both regimes of operation (see Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig4">4b, d</a> and Supplementary Note <a data-track="click" data-track-label="link" data-track-action="supplementary material anchor" href="/articles/s41467-018-06743-8#MOESM1">3</a>). In the SASE mode (Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig4">4d</a>), we observed the typical behaviour measured also at other SASE FEL sources<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 14" title="Singer, A. et al. Hanbury Brown-Twiss interferometry at a free-electron laser. Phys. Rev. Lett. 111, 034802 (2013). Erratum: 117, 239903(E) (2016)." href="/articles/s41467-018-06743-8#ref-CR14" id="ref-link-section-d141568212e1308">14</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 15" title="Gorobtsov, O. Yu et al. Statistical properties of a free-electron laser revealed by Hanbury Brown-Twiss interferometry. Phys. Rev. A 95, 023843 (2017)." href="/articles/s41467-018-06743-8#ref-CR15" id="ref-link-section-d141568212e1311">15</a></sup> with saturation at the narrower bandwidth values. We found that this saturation value was smaller (0.5) than the expected value of unity. Such behaviour was observed previously<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 15" title="Gorobtsov, O. Yu et al. Statistical properties of a free-electron laser revealed by Hanbury Brown-Twiss interferometry. Phys. Rev. A 95, 023843 (2017)." href="/articles/s41467-018-06743-8#ref-CR15" id="ref-link-section-d141568212e1315">15</a></sup> and may be explained by the limited spectrometer resolving power (see Supplementary Note <a data-track="click" data-track-label="link" data-track-action="supplementary material anchor" href="/articles/s41467-018-06743-8#MOESM1">4</a>). In the seeded mode, we observed similar behaviour of the dispersion values (see Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig4">4b</a>), but the saturation value corresponding to a narrow bandwidth was much lower, about 0.07.</p></div></div></section><section data-title="Discussion"><div class="c-article-section" id="Sec5-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Sec5">Discussion</h2><div class="c-article-section__content" id="Sec5-content"><p>For coherent laser radiation we expect the <i>g</i><sup>(2)</sup> function to be equal to one in the whole spatial and spectral range<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 3" title="Loudon, R. The Quantum Theory of Light. 3rd edn, (Oxford University Press, Great Britain, 2000)." href="/articles/s41467-018-06743-8#ref-CR3" id="ref-link-section-d141568212e1338">3</a></sup>. The residual contribution of 2–7% at FERMI may be attributed to a combination of incoherent sources of noise and variations of external parameters, such as electron beam energy or trajectory. Even if stabilised by feedbacks, these parameters are subject to shot-to-shot variations affecting the properties of the emitted light. Such fluctuations do not affect the coherence of individual pulses, but may affect the average value in Eq. (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ1">1</a>). Among genuine chaotic contributions, a residual contribution from microbunching instability may be mixing noise with the coherent energy modulation of the seed (see Supplementary Note <a data-track="click" data-track-label="link" data-track-action="supplementary material anchor" href="/articles/s41467-018-06743-8#MOESM1">4</a>). In a seeded FEL, the statistical fluctuations of the seed laser itself are translated to the XUV by the harmonic conversion process. Values of <i>g</i><sup>(2)</sup> higher than one are often observed in optical lasers<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 26" title="Lebreton, A. et al. Unequivocal differentiation of coherent and chaotic light through interferometric photon correlation measurements. Phys. Rev. Lett. 110, 163603 (2013)." href="/articles/s41467-018-06743-8#ref-CR26" id="ref-link-section-d141568212e1353">26</a></sup>, caused by mixing of chaotic radiation or quantum noise with the coherent laser radiation.</p><p>A combination of HBT interferometry and spectral measurements allowed us to demonstrate that a seeded FEL is fundamentally different in its statistical properties from a SASE-based FEL. These measurements are a decisive step forward in understanding the basic properties of FELs. While SASE FELs behave statistically as chaotic sources, the seeded FERMI FEL is equivalent in its statistical properties to a coherent laser in the definition of Glauber. Importantly, the degeneracy parameter (number of photons in a single mode) for the seeded FEL FERMI reaches a number as high as 10<sup>11</sup>–10<sup>12</sup>. This is by two orders of magnitude higher than in the case of SASE FELs<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 14" title="Singer, A. et al. Hanbury Brown-Twiss interferometry at a free-electron laser. Phys. Rev. Lett. 111, 034802 (2013). Erratum: 117, 239903(E) (2016)." href="/articles/s41467-018-06743-8#ref-CR14" id="ref-link-section-d141568212e1364">14</a></sup>, where a monochromator has to be used to pass a single longitudinal mode<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 18" title="Usenko, S. et al. Attosecond interferometry with self-amplified spontaneous emission of a free-electron laser. Nat. Commun. 8, 15626 (2017)." href="/articles/s41467-018-06743-8#ref-CR18" id="ref-link-section-d141568212e1368">18</a></sup>.</p><p>By performing high-order correlation analysis we foresee that a range of quantum optics experiments previously explored with optical fields may be performed with X-rays. For example, the Hong–Ou–Mandel effect<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 27" title="Hong, C. K., Ou, Z. Y. & Mandel, L. Measurement of subpicosecond time intervals between two photons by interference. Phys. Rev. Lett. 59, 2044 (1987)." href="/articles/s41467-018-06743-8#ref-CR27" id="ref-link-section-d141568212e1375">27</a></sup>, in which the quantum interference of indistinguishable photons is more intense than that of classical waves, should be observable with the light from FERMI. Coincidence detection by two detectors (second-order intensity correlation measurements) may resolve a still open question on diffraction of stimulated emission with intense FEL light<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 28" title="Stöhr, J. Two-photon X-ray diffraction. Phys. Rev. Lett. 118, 024801 (2017)." href="/articles/s41467-018-06743-8#ref-CR28" id="ref-link-section-d141568212e1379">28</a></sup>. The application of ideas and methods based on high-order coherence at X-ray energies is in its early stage of development<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 4" title="Oppel, S., Wiegner, R., Agarwal, G. S. & von Zanthier, J. Directional superradiant emission from statistically independent incoherent nonclassical and classical sources. Phys. Rev. Lett. 113, 263606 (2014)." href="/articles/s41467-018-06743-8#ref-CR4" id="ref-link-section-d141568212e1383">4</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 5" title="Schneider, R. et al. Quantum imaging with incoherently scattered light from a free-electron laser. Nat. Phys. 14, 126–129 (2018)." href="/articles/s41467-018-06743-8#ref-CR5" id="ref-link-section-d141568212e1386">5</a></sup>, and the knowledge that second-order coherent FEL light is available at FERMI permits the design and execution of next generation experiments, that strongly rely on high-order statistical properties of the radiation. An open and intriguing question regards the statistical properties of self-seeded FELs<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 29" title="Geloni, G., Kocharyan, V. & Saldin, E. A novel self-seeding scheme for hard x-ray FELs. J. Mod. Opt. 58, 1391–1403 (2011)." href="/articles/s41467-018-06743-8#ref-CR29" id="ref-link-section-d141568212e1390">29</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 30" title="Amann, J. et al. Demonstration of self-seeding in a hard-X-ray free-electron laser. Nat. Photon. 6, 693–698 (2012)." href="/articles/s41467-018-06743-8#ref-CR30" id="ref-link-section-d141568212e1393">30</a></sup>. In contrast to an externally seeded FEL, this perfectly first-order coherent source may show different second-order statistical properties.</p></div></div></section><section data-title="Methods"><div class="c-article-section" id="Sec6-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Sec6">Methods</h2><div class="c-article-section__content" id="Sec6-content"><h3 class="c-article__sub-heading" id="Sec7">Correlation functions</h3><p>The normalised first-order correlation function is defined as<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 3" title="Loudon, R. The Quantum Theory of Light. 3rd edn, (Oxford University Press, Great Britain, 2000)." href="/articles/s41467-018-06743-8#ref-CR3" id="ref-link-section-d141568212e1409">3</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 25" title="Goodman, J. W. Statistical Optics. (Wiley, Hoboken, NJ, 2000)." href="/articles/s41467-018-06743-8#ref-CR25" id="ref-link-section-d141568212e1412">25</a></sup></p><div id="Equ2" class="c-article-equation"><div class="c-article-equation__content"><span class="mathjax-tex">$$g^{\left( 1 \right)}\left( {{\bf{r}}_1,{\bf{r}}_2} \right) = \left\langle {E^ \ast \left( {{\bf{r}}_1} \right)E\left( {{\bf{r}}_2} \right)} \right\rangle /\left\langle {\sqrt {I\left( {{\bf{r}}_1} \right)} } \right\rangle \left\langle {\sqrt {I\left( {{\bf{r}}_2} \right)} } \right\rangle ,$$</span></div><div class="c-article-equation__number"> (2) </div></div><p>where <i>E</i>(<b>r</b><sub><b>1</b></sub>) and <i>E</i>(<b>r</b><sub><b>2</b></sub>) are complex amplitudes of the wave field at different spatial positions measured simultaneously, and the brackets <span class="mathjax-tex">$\left\langle \ldots \right\rangle$</span> denote averaging over a large ensemble of different radiation pulses. The first-order correlation function (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ2">2</a>) represents the mutual intensity function<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 25" title="Goodman, J. W. Statistical Optics. (Wiley, Hoboken, NJ, 2000)." href="/articles/s41467-018-06743-8#ref-CR25" id="ref-link-section-d141568212e1530">25</a></sup>.</p><p>The normalised second-order intensity correlation function <i>g</i><sup>(2)</sup>(<b>r</b><sub><b>1</b></sub>, <b>r</b><sub><b>2</b></sub>) is defined by Eq. (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ1">1</a>). An important quantity derived from the second-order intensity correlation function (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ1">1</a>) is the contrast defined as</p><div id="Equ3" class="c-article-equation"><div class="c-article-equation__content"><span class="mathjax-tex">$$\zeta _2\left( {\bf{r}} \right) = g^{\left( 2 \right)}\left( {{\bf{r}},{\bf{r}}} \right) - 1.$$</span></div><div class="c-article-equation__number"> (3) </div></div><p>Chaotic sources with Gaussian statistics may be described by the following intensity correlation function<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 14" title="Singer, A. et al. Hanbury Brown-Twiss interferometry at a free-electron laser. Phys. Rev. Lett. 111, 034802 (2013). Erratum: 117, 239903(E) (2016)." href="/articles/s41467-018-06743-8#ref-CR14" id="ref-link-section-d141568212e1596">14</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 31" title="Ikonen, E. Interference effects between independent gamma rays. Phys. Rev. Lett. 68, 2759–2761 (1992)." href="/articles/s41467-018-06743-8#ref-CR31" id="ref-link-section-d141568212e1599">31</a></sup></p><div id="Equ4" class="c-article-equation"><div class="c-article-equation__content"><span class="mathjax-tex">$$g^{\left( 2 \right)}\left( {{\bf{r}}_1,{\bf{r}}_2} \right) = 1 + \zeta _2\left( {D_\omega } \right)\left| {g^{\left( 1 \right)}\left( {{\bf{r}}_1,{\bf{r}}_2} \right)} \right|^2.$$</span></div><div class="c-article-equation__number"> (4) </div></div><p>Here <i>ζ</i><sub>2</sub>(<i>D</i><sub><i>ω</i></sub>) is the contrast function defined in (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ3">3</a>), which in the case of chaotic sources depends strongly on the radiation frequency bandwidth <i>D</i><sub><i>ω</i></sub> and <i>g</i><sup>(1)</sup>(<b>r</b><sub><b>1</b></sub>, <b>r</b><sub><b>2</b></sub>) is the first-order correlation function (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ2">2</a>). In the case of a chaotic pulsed beam, <i>ζ</i><sub>2</sub>(<i>D</i><sub><i>ω</i></sub>) is determined by <i>τ</i><sub>c</sub>/<i>T</i>, where <i>τ</i><sub>c</sub> = 2<i>π</i>/<i>D</i><sub><i>ω</i></sub> is the coherence time and <i>T</i> is the pulse duration of the FEL radiation<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 31" title="Ikonen, E. Interference effects between independent gamma rays. Phys. Rev. Lett. 68, 2759–2761 (1992)." href="/articles/s41467-018-06743-8#ref-CR31" id="ref-link-section-d141568212e1752">31</a></sup>. In this limit the number of longitudinal modes <i>M</i><sub>t</sub> defined as <i>M</i><sub>t</sub> = <i>T</i>/<i>τ</i><sub>c</sub> is inversely proportional to the contrast function <i>ζ</i><sub>2</sub>(<i>D</i><sub><i>ω</i></sub>). Notice also that for a perfect chaotic Gaussian source <i>g</i><sup>(2)</sup>(<b>r</b>, <b>r</b>) = 1 + <i>ζ</i><sub>2</sub>(<i>D</i><sub><i>ω</i></sub>) and does not depend on position <b>r</b>.</p><h3 class="c-article__sub-heading" id="Sec8">Experimental details</h3><p>We performed the experiment at the beamline DiProI of the FERMI using the FEL-2 source with both seeded and SASE modes. The scheme of the experiment is shown in Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig1">1</a>. The double cascade source FEL-2 tuned to the wavelength of 10.9 nm and average power of 11 μJ per pulse was used to generate seeded and SASE radiation. The radiation was focused with a Kirkpatrick–Baez optical system, and the intensity distribution was detected at a distance of 0.5 m from the focus (transmission of the beamline was about 65–70% at 10.9 nm wavelength). The beam divergence, after the refocusing optics, was about 1.0 mrad. An in-vacuum Andor Ikon CCD detector with 2048 × 2048 pixels of 13.5 × 13.5 μm<sup>2</sup> size was used for intensity measurements of the direct beam. A small portion of the beam was partially diffracted by a grating to the shot-by-shot PRESTO spectrometer<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 32" title="Svetina, C. et al. PRESTO, the on-line photon energy spectrometer at FERMI: design, features and commissioning results. J. Synchrotron Rad. 23, 35–42 (2016)." href="/articles/s41467-018-06743-8#ref-CR32" id="ref-link-section-d141568212e1820">32</a></sup>. This diagnostic provides a spectrum of each pulse simultaneously with the measurements at the DiProI end station. Several series of both direct beam and spectral images at different FEL parameters were recorded. Each series consisted of 10<sup>4</sup> shots, measured with 10 Hz frequency.</p><p>The spectrometer is characterised by a resolving power of 1.8 × 10<sup>4</sup> at 10.9 nm<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 32" title="Svetina, C. et al. PRESTO, the on-line photon energy spectrometer at FERMI: design, features and commissioning results. J. Synchrotron Rad. 23, 35–42 (2016)." href="/articles/s41467-018-06743-8#ref-CR32" id="ref-link-section-d141568212e1831">32</a></sup>, corresponding to the separation of two spectral lines of about 6 × 10<sup>−4</sup> nm. This implies that the spectrometer resolving power is sufficient to correctly measure the width of the seeded FEL pulses (5 × 10<sup>−3</sup> nm). The SASE spectrum contains spikes resulting from the spectral superposition of uncorrelated temporal spikes separated in time. The duration of the temporal spikes can be derived from the SASE average spectral width (6.5 × 10<sup>−2</sup> nm) and corresponds to about 6 fs. The finest structure in the spectral distribution depends on maximum temporal separation between the spikes. Assuming this separation to be of the order of 1 ps, i.e. the duration of the electron current (see Supplementary Note <a data-track="click" data-track-label="link" data-track-action="supplementary material anchor" href="/articles/s41467-018-06743-8#MOESM1">4</a>) we calculate the width of these finest structures in the spectrum to be about 4 × 10<sup>−4</sup> nm, which would require a resolving power of about 3 × 10<sup>−4</sup> to be observable. For this reason we found that the saturation value in Fig. <a data-track="click" data-track-label="link" data-track-action="figure anchor" href="/articles/s41467-018-06743-8#Fig4">4d</a> was smaller (0.5) than the expected value of unity. At the maximum spectral resolution of the spectrometer, it may still collect about two longitudinal modes which gives the contrast value in Eq. (<a data-track="click" data-track-label="link" data-track-action="equation anchor" href="/articles/s41467-018-06743-8#Equ3">3</a>) of about 0.5.</p><h3 class="c-article__sub-heading" id="Sec9">Intensity distribution for chaotic and laser sources</h3><p>In the case of a chaotic source obeying Gaussian statistics, the probability <i>p</i>(<i>I</i>) that the total intensity of the pulse takes value <i>I</i>, follows a Gamma distribution<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 25" title="Goodman, J. W. Statistical Optics. (Wiley, Hoboken, NJ, 2000)." href="/articles/s41467-018-06743-8#ref-CR25" id="ref-link-section-d141568212e1872">25</a>,<a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 33" title="Saldin, E., Schneidmiller, E. & Yurkov, M. Statistical properties of radiation from VUV and x-ray free electron laser. Opt. Comm. 148, 383–403 (1998)." href="/articles/s41467-018-06743-8#ref-CR33" id="ref-link-section-d141568212e1875">33</a></sup></p><div id="Equ5" class="c-article-equation"><div class="c-article-equation__content"><span class="mathjax-tex">$$p\left( I \right) = \frac{{M^M}}{{{\mathrm{\Gamma }}\left( M \right)}}\left( {\frac{I}{{\left\langle I \right\rangle }}} \right)^{M - 1}{\mathrm{{exp}}}\left( { - M\frac{I}{{\left\langle I \right\rangle }}} \right),$$</span></div><div class="c-article-equation__number"> (5) </div></div><p>where <i>M</i> is the number of degrees of freedom, or modes, and 〈<i>I</i>〉 is an average intensity of the pulse.</p><p>In the case of laser radiation, the probability distribution of the total intensity may be described as originating from various noise effects and obeys a normal distribution<sup><a data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 25" title="Goodman, J. W. Statistical Optics. (Wiley, Hoboken, NJ, 2000)." href="/articles/s41467-018-06743-8#ref-CR25" id="ref-link-section-d141568212e1944">25</a></sup></p><div id="Equ6" class="c-article-equation"><div class="c-article-equation__content"><span class="mathjax-tex">$$p\left( I \right) = \frac{1}{{\sqrt {2\pi \sigma ^2} }}{\mathrm{{exp}}}\left( { - \frac{{\left( {I - \left\langle I \right\rangle } \right)^2}}{{2\sigma ^2}}} \right),$$</span></div><div class="c-article-equation__number"> (6) </div></div><p>where <i>σ</i> is the width of the distribution.</p></div></div></section> </div> <div class="u-mt-32"> <section data-title="Data availability"><div class="c-article-section" id="data-availability-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="data-availability">Data availability</h2><div class="c-article-section__content" id="data-availability-content"> <p>All relevant data are available from the corresponding author.</p> </div></div></section><section data-title="Change history"><div class="c-article-section" id="change-history-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="change-history">Change history</h2><div class="c-article-section__content" id="change-history-content"><ul class="c-article-change-list"><li class="c-article-change-list__item u-mb-24" id="chg1"><ins datetime="2019-11-13"><h3 class="c-article-change-list__heading u-h3 u-pr-8 u-display-inline">13 November 2019</h3><div class="c-article-change-list__details"><p>An amendment to this paper has been published and can be accessed via a link at the top of the paper.</p></div></ins></li></ul></div></div></section><div id="MagazineFulltextArticleBodySuffix"><section aria-labelledby="Bib1" data-title="References"><div class="c-article-section" id="Bib1-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Bib1">References</h2><div class="c-article-section__content" id="Bib1-content"><div data-container-section="references"><ol class="c-article-references" data-track-component="outbound reference" data-track-context="references section"><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="1."><p class="c-article-references__text" id="ref-CR1">Glauber, R. J. The quantum theory of optical coherence. <i>Phys. Rev.</i> <b>130</b>, 2529–2539 (1963).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1103/PhysRev.130.2529" data-track-item_id="10.1103/PhysRev.130.2529" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1103%2FPhysRev.130.2529" aria-label="Article reference 1" data-doi="10.1103/PhysRev.130.2529">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=1963PhRv..130.2529G" aria-label="ADS reference 1">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="mathscinet reference" data-track-action="mathscinet reference" href="http://www.ams.org/mathscinet-getitem?mr=156576" aria-label="MathSciNet reference 1">MathSciNet</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 1" href="http://scholar.google.com/scholar_lookup?&title=The%20quantum%20theory%20of%20optical%20coherence&journal=Phys.%20Rev.&doi=10.1103%2FPhysRev.130.2529&volume=130&pages=2529-2539&publication_year=1963&author=Glauber%2CRJ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="2."><p class="c-article-references__text" id="ref-CR2">Arecchi, F. T., Gatti, E. & Sona, A. Time distribution of photons from coherent and Gaussian sources. <i>Phys. Lett.</i> <b>20</b>, 27–29 (1966).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/0031-9163(66)91034-1" data-track-item_id="10.1016/0031-9163(66)91034-1" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2F0031-9163%2866%2991034-1" aria-label="Article reference 2" data-doi="10.1016/0031-9163(66)91034-1">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=1966PhL....20...27A" aria-label="ADS reference 2">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaF28XlslCgtg%3D%3D" aria-label="CAS reference 2">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 2" href="http://scholar.google.com/scholar_lookup?&title=Time%20distribution%20of%20photons%20from%20coherent%20and%20Gaussian%20sources&journal=Phys.%20Lett.&doi=10.1016%2F0031-9163%2866%2991034-1&volume=20&pages=27-29&publication_year=1966&author=Arecchi%2CFT&author=Gatti%2CE&author=Sona%2CA"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="3."><p class="c-article-references__text" id="ref-CR3">Loudon, R. <i>The Quantum Theory of Light</i>. 3rd edn, (Oxford University Press, Great Britain, 2000).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="math reference" data-track-action="math reference" href="http://www.emis.de/MATH-item?1009.81003" aria-label="MATH reference 3">MATH</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 3" href="http://scholar.google.com/scholar_lookup?&title=The%20Quantum%20Theory%20of%20Light&publication_year=2000&author=Loudon%2CR"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="4."><p class="c-article-references__text" id="ref-CR4">Oppel, S., Wiegner, R., Agarwal, G. S. & von Zanthier, J. Directional superradiant emission from statistically independent incoherent nonclassical and classical sources. <i>Phys. Rev. Lett.</i> <b>113</b>, 263606 (2014).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1103/PhysRevLett.113.263606" data-track-item_id="10.1103/PhysRevLett.113.263606" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1103%2FPhysRevLett.113.263606" aria-label="Article reference 4" data-doi="10.1103/PhysRevLett.113.263606">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2014PhRvL.113z3606O" aria-label="ADS reference 4">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:STN:280:DC%2BC2MvptFynsg%3D%3D" aria-label="CAS reference 4">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 4" href="http://scholar.google.com/scholar_lookup?&title=Directional%20superradiant%20emission%20from%20statistically%20independent%20incoherent%20nonclassical%20and%20classical%20sources&journal=Phys.%20Rev.%20Lett.&doi=10.1103%2FPhysRevLett.113.263606&volume=113&publication_year=2014&author=Oppel%2CS&author=Wiegner%2CR&author=Agarwal%2CGS&author=Zanthier%2CJ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="5."><p class="c-article-references__text" id="ref-CR5">Schneider, R. et al. Quantum imaging with incoherently scattered light from a free-electron laser. <i>Nat. Phys.</i> <b>14</b>, 126–129 (2018).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/nphys4301" data-track-item_id="10.1038/nphys4301" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2Fnphys4301" aria-label="Article reference 5" data-doi="10.1038/nphys4301">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BC2sXhslems7zF" aria-label="CAS reference 5">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 5" href="http://scholar.google.com/scholar_lookup?&title=Quantum%20imaging%20with%20incoherently%20scattered%20light%20from%20a%20free-electron%20laser&journal=Nat.%20Phys.&doi=10.1038%2Fnphys4301&volume=14&pages=126-129&publication_year=2018&author=Schneider%2CR"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="6."><p class="c-article-references__text" id="ref-CR6">Ackermann, W. et al. Operation of a free-electron laser from the extreme ultraviolet to the water window. <i>Nat. Photon.</i> <b>1</b>, 336–342 (2007).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/nphoton.2007.76" data-track-item_id="10.1038/nphoton.2007.76" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2Fnphoton.2007.76" aria-label="Article reference 6" data-doi="10.1038/nphoton.2007.76">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2007NaPho...1..336A" aria-label="ADS reference 6">ADS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 6" href="http://scholar.google.com/scholar_lookup?&title=Operation%20of%20a%20free-electron%20laser%20from%20the%20extreme%20ultraviolet%20to%20the%20water%20window&journal=Nat.%20Photon.&doi=10.1038%2Fnphoton.2007.76&volume=1&pages=336-342&publication_year=2007&author=Ackermann%2CW"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="7."><p class="c-article-references__text" id="ref-CR7">Allaria, E. et al. Two-stage seeded soft-X-ray free-electron laser. <i>Nat. Photon.</i> <b>7</b>, 913–918 (2013).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/nphoton.2013.277" data-track-item_id="10.1038/nphoton.2013.277" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2Fnphoton.2013.277" aria-label="Article reference 7" data-doi="10.1038/nphoton.2013.277">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2013NaPho...7..913A" aria-label="ADS reference 7">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BC3sXhs1CitLjF" aria-label="CAS reference 7">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 7" href="http://scholar.google.com/scholar_lookup?&title=Two-stage%20seeded%20soft-X-ray%20free-electron%20laser&journal=Nat.%20Photon.&doi=10.1038%2Fnphoton.2013.277&volume=7&pages=913-918&publication_year=2013&author=Allaria%2CE"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="8."><p class="c-article-references__text" id="ref-CR8">Emma, P. et al. First lasing and operation of an ångstrom-wavelength free-electron laser. <i>Nat. Photon.</i> <b>4</b>, 641–647 (2010).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/nphoton.2010.176" data-track-item_id="10.1038/nphoton.2010.176" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2Fnphoton.2010.176" aria-label="Article reference 8" data-doi="10.1038/nphoton.2010.176">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2010NaPho...4..641E" aria-label="ADS reference 8">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BC3cXhtV2hsb%2FP" aria-label="CAS reference 8">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 8" href="http://scholar.google.com/scholar_lookup?&title=First%20lasing%20and%20operation%20of%20an%20%C3%A5ngstrom-wavelength%20free-electron%20laser&journal=Nat.%20Photon.&doi=10.1038%2Fnphoton.2010.176&volume=4&pages=641-647&publication_year=2010&author=Emma%2CP"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="9."><p class="c-article-references__text" id="ref-CR9">Ishikawa, T. et al. A compact x-ray free-electron laser emitting in the sub-angstrom region. <i>Nat. Photon.</i> <b>6</b>, 540–544 (2012).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/nphoton.2012.141" data-track-item_id="10.1038/nphoton.2012.141" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2Fnphoton.2012.141" aria-label="Article reference 9" data-doi="10.1038/nphoton.2012.141">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2012NaPho...6..540I" aria-label="ADS reference 9">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BC38XovFyrtLo%3D" aria-label="CAS reference 9">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 9" href="http://scholar.google.com/scholar_lookup?&title=A%20compact%20x-ray%20free-electron%20laser%20emitting%20in%20the%20sub-angstrom%20region&journal=Nat.%20Photon.&doi=10.1038%2Fnphoton.2012.141&volume=6&pages=540-544&publication_year=2012&author=Ishikawa%2CT"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="10."><p class="c-article-references__text" id="ref-CR10">Altarelli, M. et al. <i>The European X-ray Free-electron Laser—technical Design Report</i>. Technical Report DESY 2006-097. European XFEL Project Team (Deutsches Elektronen-Synchrotron, Hamburg, 2006).</p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="11."><p class="c-article-references__text" id="ref-CR11">Saldin, E., Schneidmiller, E. & Yurkov, M. <i>The Physics of Free Electron Laser</i>. (Springer-Verlag, Berlin, 2000).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="noopener" data-track-label="10.1007/978-3-662-04066-9" data-track-item_id="10.1007/978-3-662-04066-9" data-track-value="book reference" data-track-action="book reference" href="https://link.springer.com/doi/10.1007/978-3-662-04066-9" aria-label="Book reference 11" data-doi="10.1007/978-3-662-04066-9">Book</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 11" href="http://scholar.google.com/scholar_lookup?&title=The%20Physics%20of%20Free%20Electron%20Laser&doi=10.1007%2F978-3-662-04066-9&publication_year=2000&author=Saldin%2CE&author=Schneidmiller%2CE&author=Yurkov%2CM"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="12."><p class="c-article-references__text" id="ref-CR12">Vartanyants, I. A. et al. Coherence properties of individual femtosecond pulses of an x-ray free-electron laser. <i>Phys. Rev. Lett.</i> <b>107</b>, 144801 (2011).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1103/PhysRevLett.107.144801" data-track-item_id="10.1103/PhysRevLett.107.144801" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1103%2FPhysRevLett.107.144801" aria-label="Article reference 12" data-doi="10.1103/PhysRevLett.107.144801">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2011PhRvL.107n4801V" aria-label="ADS reference 12">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:STN:280:DC%2BC38%2FhslChug%3D%3D" aria-label="CAS reference 12">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 12" href="http://scholar.google.com/scholar_lookup?&title=Coherence%20properties%20of%20individual%20femtosecond%20pulses%20of%20an%20x-ray%20free-electron%20laser&journal=Phys.%20Rev.%20Lett.&doi=10.1103%2FPhysRevLett.107.144801&volume=107&publication_year=2011&author=Vartanyants%2CIA"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="13."><p class="c-article-references__text" id="ref-CR13">Singer, A. et al. Spatial and temporal coherence properties of single free-electron laser pulses. <i>Opt. Express</i> <b>20</b>, 17480–17495 (2012).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1364/OE.20.017480" data-track-item_id="10.1364/OE.20.017480" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1364%2FOE.20.017480" aria-label="Article reference 13" data-doi="10.1364/OE.20.017480">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2012OExpr..2017480S" aria-label="ADS reference 13">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BC38XhtFGgt7vK" aria-label="CAS reference 13">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 13" href="http://scholar.google.com/scholar_lookup?&title=Spatial%20and%20temporal%20coherence%20properties%20of%20single%20free-electron%20laser%20pulses&journal=Opt.%20Express&doi=10.1364%2FOE.20.017480&volume=20&pages=17480-17495&publication_year=2012&author=Singer%2CA"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="14."><p class="c-article-references__text" id="ref-CR14">Singer, A. et al. Hanbury Brown-Twiss interferometry at a free-electron laser. <i>Phys. Rev. Lett.</i> <b>111</b>, 034802 (2013). Erratum: <b>117</b>, 239903(E) (2016).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1103/PhysRevLett.111.034802" data-track-item_id="10.1103/PhysRevLett.111.034802" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1103%2FPhysRevLett.111.034802" aria-label="Article reference 14" data-doi="10.1103/PhysRevLett.111.034802">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2013PhRvL.111c4802S" aria-label="ADS reference 14">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:STN:280:DC%2BC3sfmsFCmtg%3D%3D" aria-label="CAS reference 14">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 14" href="http://scholar.google.com/scholar_lookup?&title=Hanbury%20Brown-Twiss%20interferometry%20at%20a%20free-electron%20laser&journal=Phys.%20Rev.%20Lett.&doi=10.1103%2FPhysRevLett.111.034802&volume=111&publication_year=2013&author=Singer%2CA"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="15."><p class="c-article-references__text" id="ref-CR15">Gorobtsov, O. Yu et al. Statistical properties of a free-electron laser revealed by Hanbury Brown-Twiss interferometry. <i>Phys. Rev. A</i> <b>95</b>, 023843 (2017).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1103/PhysRevA.95.023843" data-track-item_id="10.1103/PhysRevA.95.023843" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1103%2FPhysRevA.95.023843" aria-label="Article reference 15" data-doi="10.1103/PhysRevA.95.023843">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2017PhRvA..95b3843G" aria-label="ADS reference 15">ADS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 15" href="http://scholar.google.com/scholar_lookup?&title=Statistical%20properties%20of%20a%20free-electron%20laser%20revealed%20by%20Hanbury%20Brown-Twiss%20interferometry&journal=Phys.%20Rev.%20A&doi=10.1103%2FPhysRevA.95.023843&volume=95&publication_year=2017&author=Gorobtsov%2COYu"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="16."><p class="c-article-references__text" id="ref-CR16">Gorobtsov, O. Yu et al. Diffraction based Hanbury Brown and Twiss interferometry performed at a hard x-ray free-electron laser. <i>Sci. Rep.</i> <b>8</b>, 2219 (2018).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/s41598-018-19793-1" data-track-item_id="10.1038/s41598-018-19793-1" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2Fs41598-018-19793-1" aria-label="Article reference 16" data-doi="10.1038/s41598-018-19793-1">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2018NatSR...8.2219G" aria-label="ADS reference 16">ADS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 16" href="http://scholar.google.com/scholar_lookup?&title=Diffraction%20based%20Hanbury%20Brown%20and%20Twiss%20interferometry%20performed%20at%20a%20hard%20x-ray%20free-electron%20laser&journal=Sci.%20Rep.&doi=10.1038%2Fs41598-018-19793-1&volume=8&publication_year=2018&author=Gorobtsov%2COYu"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="17."><p class="c-article-references__text" id="ref-CR17">Prince, K. C. et al. Coherent control with a short-wavelength free-electron laser. <i>Nat. Photon.</i> <b>10</b>, 176–179 (2016).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/nphoton.2016.13" data-track-item_id="10.1038/nphoton.2016.13" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2Fnphoton.2016.13" aria-label="Article reference 17" data-doi="10.1038/nphoton.2016.13">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2016NaPho..10..176P" aria-label="ADS reference 17">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BC28XisFKhurk%3D" aria-label="CAS reference 17">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 17" href="http://scholar.google.com/scholar_lookup?&title=Coherent%20control%20with%20a%20short-wavelength%20free-electron%20laser&journal=Nat.%20Photon.&doi=10.1038%2Fnphoton.2016.13&volume=10&pages=176-179&publication_year=2016&author=Prince%2CKC"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="18."><p class="c-article-references__text" id="ref-CR18">Usenko, S. et al. Attosecond interferometry with self-amplified spontaneous emission of a free-electron laser. <i>Nat. Commun.</i> <b>8</b>, 15626 (2017).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/ncomms15626" data-track-item_id="10.1038/ncomms15626" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2Fncomms15626" aria-label="Article reference 18" data-doi="10.1038/ncomms15626">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2017NatCo...815626U" aria-label="ADS reference 18">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BC2sXovFCgt7w%3D" aria-label="CAS reference 18">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 18" href="http://scholar.google.com/scholar_lookup?&title=Attosecond%20interferometry%20with%20self-amplified%20spontaneous%20emission%20of%20a%20free-electron%20laser&journal=Nat.%20Commun.&doi=10.1038%2Fncomms15626&volume=8&publication_year=2017&author=Usenko%2CS"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="19."><p class="c-article-references__text" id="ref-CR19">De Ninno, G. et al. Single-shot spectro-temporal characterization of XUV pulses from a seeded free-electron laser. <i>Nat. Commun.</i> <b>6</b>, 8075 (2015).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/ncomms9075" data-track-item_id="10.1038/ncomms9075" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2Fncomms9075" aria-label="Article reference 19" data-doi="10.1038/ncomms9075">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2015NatCo...6.8035N" aria-label="ADS reference 19">ADS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 19" href="http://scholar.google.com/scholar_lookup?&title=Single-shot%20spectro-temporal%20characterization%20of%20XUV%20pulses%20from%20a%20seeded%20free-electron%20laser&journal=Nat.%20Commun.&doi=10.1038%2Fncomms9075&volume=6&publication_year=2015&author=Ninno%2CGD"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="20."><p class="c-article-references__text" id="ref-CR20">Gauthier, D. et al. Spectrotemporal shaping of seeded free-electron laser pulses. <i>Phys. Rev. Lett.</i> <b>115</b>, 114801 (2015).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1103/PhysRevLett.115.114801" data-track-item_id="10.1103/PhysRevLett.115.114801" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1103%2FPhysRevLett.115.114801" aria-label="Article reference 20" data-doi="10.1103/PhysRevLett.115.114801">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2015PhRvL.115k4801G" aria-label="ADS reference 20">ADS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 20" href="http://scholar.google.com/scholar_lookup?&title=Spectrotemporal%20shaping%20of%20seeded%20free-electron%20laser%20pulses&journal=Phys.%20Rev.%20Lett.&doi=10.1103%2FPhysRevLett.115.114801&volume=115&publication_year=2015&author=Gauthier%2CD"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="21."><p class="c-article-references__text" id="ref-CR21">Hanbury Brown, R. & Twiss, R. Q. Correlation between photons in two coherent beams of light. <i>Nature</i> <b>177</b>, 27–32 (1956).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/177027a0" data-track-item_id="10.1038/177027a0" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2F177027a0" aria-label="Article reference 21" data-doi="10.1038/177027a0">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=1956Natur.177...27B" aria-label="ADS reference 21">ADS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 21" href="http://scholar.google.com/scholar_lookup?&title=Correlation%20between%20photons%20in%20two%20coherent%20beams%20of%20light&journal=Nature&doi=10.1038%2F177027a0&volume=177&pages=27-32&publication_year=1956&author=Hanbury%20Brown%2CR&author=Twiss%2CRQ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="22."><p class="c-article-references__text" id="ref-CR22">Hanbury Brown, R. & Twiss, R. Q. A test of a new type of stellar interferometer on Sirius. <i>Nature</i> <b>178</b>, 1046–1048 (1956).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/1781046a0" data-track-item_id="10.1038/1781046a0" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2F1781046a0" aria-label="Article reference 22" data-doi="10.1038/1781046a0">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=1956Natur.178.1046H" aria-label="ADS reference 22">ADS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 22" href="http://scholar.google.com/scholar_lookup?&title=A%20test%20of%20a%20new%20type%20of%20stellar%20interferometer%20on%20Sirius&journal=Nature&doi=10.1038%2F1781046a0&volume=178&pages=1046-1048&publication_year=1956&author=Hanbury%20Brown%2CR&author=Twiss%2CRQ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="23."><p class="c-article-references__text" id="ref-CR23">Paul, H. Interference between independent photons. <i>Rev. Mod. Phys.</i> <b>58</b>, 209–231 (1986).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1103/RevModPhys.58.209" data-track-item_id="10.1103/RevModPhys.58.209" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1103%2FRevModPhys.58.209" aria-label="Article reference 23" data-doi="10.1103/RevModPhys.58.209">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=1986RvMP...58..209P" aria-label="ADS reference 23">ADS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 23" href="http://scholar.google.com/scholar_lookup?&title=Interference%20between%20independent%20photons&journal=Rev.%20Mod.%20Phys.&doi=10.1103%2FRevModPhys.58.209&volume=58&pages=209-231&publication_year=1986&author=Paul%2CH"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="24."><p class="c-article-references__text" id="ref-CR24">Penco, G. et al. Optical Klystron enhancement to self amplified spontaneous emission at FERMI. <i>Photonics</i> <b>4</b>, 15 (2017).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.3390/photonics4010015" data-track-item_id="10.3390/photonics4010015" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.3390%2Fphotonics4010015" aria-label="Article reference 24" data-doi="10.3390/photonics4010015">Article</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 24" href="http://scholar.google.com/scholar_lookup?&title=Optical%20Klystron%20enhancement%20to%20self%20amplified%20spontaneous%20emission%20at%20FERMI&journal=Photonics&doi=10.3390%2Fphotonics4010015&volume=4&publication_year=2017&author=Penco%2CG"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="25."><p class="c-article-references__text" id="ref-CR25">Goodman, J. W. <i>Statistical Optics</i>. (Wiley, Hoboken, NJ, 2000).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 25" href="http://scholar.google.com/scholar_lookup?&title=Statistical%20Optics&publication_year=2000&author=Goodman%2CJW"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="26."><p class="c-article-references__text" id="ref-CR26">Lebreton, A. et al. Unequivocal differentiation of coherent and chaotic light through interferometric photon correlation measurements. <i>Phys. Rev. Lett.</i> <b>110</b>, 163603 (2013).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1103/PhysRevLett.110.163603" data-track-item_id="10.1103/PhysRevLett.110.163603" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1103%2FPhysRevLett.110.163603" aria-label="Article reference 26" data-doi="10.1103/PhysRevLett.110.163603">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2013PhRvL.110p3603L" aria-label="ADS reference 26">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:STN:280:DC%2BC3snksVymsg%3D%3D" aria-label="CAS reference 26">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 26" href="http://scholar.google.com/scholar_lookup?&title=Unequivocal%20differentiation%20of%20coherent%20and%20chaotic%20light%20through%20interferometric%20photon%20correlation%20measurements&journal=Phys.%20Rev.%20Lett.&doi=10.1103%2FPhysRevLett.110.163603&volume=110&publication_year=2013&author=Lebreton%2CA"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="27."><p class="c-article-references__text" id="ref-CR27">Hong, C. K., Ou, Z. Y. & Mandel, L. Measurement of subpicosecond time intervals between two photons by interference. <i>Phys. Rev. Lett.</i> <b>59</b>, 2044 (1987).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1103/PhysRevLett.59.2044" data-track-item_id="10.1103/PhysRevLett.59.2044" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1103%2FPhysRevLett.59.2044" aria-label="Article reference 27" data-doi="10.1103/PhysRevLett.59.2044">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=1987PhRvL..59.2044H" aria-label="ADS reference 27">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaL1cXmt1Kisw%3D%3D" aria-label="CAS reference 27">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 27" href="http://scholar.google.com/scholar_lookup?&title=Measurement%20of%20subpicosecond%20time%20intervals%20between%20two%20photons%20by%20interference&journal=Phys.%20Rev.%20Lett.&doi=10.1103%2FPhysRevLett.59.2044&volume=59&publication_year=1987&author=Hong%2CCK&author=Ou%2CZY&author=Mandel%2CL"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="28."><p class="c-article-references__text" id="ref-CR28">Stöhr, J. Two-photon X-ray diffraction. <i>Phys. Rev. Lett.</i> <b>118</b>, 024801 (2017).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1103/PhysRevLett.118.024801" data-track-item_id="10.1103/PhysRevLett.118.024801" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1103%2FPhysRevLett.118.024801" aria-label="Article reference 28" data-doi="10.1103/PhysRevLett.118.024801">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2017PhRvL.118b4801S" aria-label="ADS reference 28">ADS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 28" href="http://scholar.google.com/scholar_lookup?&title=Two-photon%20X-ray%20diffraction&journal=Phys.%20Rev.%20Lett.&doi=10.1103%2FPhysRevLett.118.024801&volume=118&publication_year=2017&author=St%C3%B6hr%2CJ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="29."><p class="c-article-references__text" id="ref-CR29">Geloni, G., Kocharyan, V. & Saldin, E. A novel self-seeding scheme for hard x-ray FELs. <i>J. Mod. Opt.</i> <b>58</b>, 1391–1403 (2011).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1080/09500340.2011.586473" data-track-item_id="10.1080/09500340.2011.586473" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1080%2F09500340.2011.586473" aria-label="Article reference 29" data-doi="10.1080/09500340.2011.586473">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2011JMOp...58.1391G" aria-label="ADS reference 29">ADS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 29" href="http://scholar.google.com/scholar_lookup?&title=A%20novel%20self-seeding%20scheme%20for%20hard%20x-ray%20FELs&journal=J.%20Mod.%20Opt.&doi=10.1080%2F09500340.2011.586473&volume=58&pages=1391-1403&publication_year=2011&author=Geloni%2CG&author=Kocharyan%2CV&author=Saldin%2CE"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="30."><p class="c-article-references__text" id="ref-CR30">Amann, J. et al. Demonstration of self-seeding in a hard-X-ray free-electron laser. <i>Nat. Photon.</i> <b>6</b>, 693–698 (2012).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1038/nphoton.2012.180" data-track-item_id="10.1038/nphoton.2012.180" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1038%2Fnphoton.2012.180" aria-label="Article reference 30" data-doi="10.1038/nphoton.2012.180">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=2012NaPho...6..693A" aria-label="ADS reference 30">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BC38XhtFOgsbbO" aria-label="CAS reference 30">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 30" href="http://scholar.google.com/scholar_lookup?&title=Demonstration%20of%20self-seeding%20in%20a%20hard-X-ray%20free-electron%20laser&journal=Nat.%20Photon.&doi=10.1038%2Fnphoton.2012.180&volume=6&pages=693-698&publication_year=2012&author=Amann%2CJ"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="31."><p class="c-article-references__text" id="ref-CR31">Ikonen, E. Interference effects between independent gamma rays. <i>Phys. Rev. Lett.</i> <b>68</b>, 2759–2761 (1992).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1103/PhysRevLett.68.2759" data-track-item_id="10.1103/PhysRevLett.68.2759" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1103%2FPhysRevLett.68.2759" aria-label="Article reference 31" data-doi="10.1103/PhysRevLett.68.2759">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=1992PhRvL..68.2759I" aria-label="ADS reference 31">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:STN:280:DC%2BC2sfptVyjsg%3D%3D" aria-label="CAS reference 31">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 31" href="http://scholar.google.com/scholar_lookup?&title=Interference%20effects%20between%20independent%20gamma%20rays&journal=Phys.%20Rev.%20Lett.&doi=10.1103%2FPhysRevLett.68.2759&volume=68&pages=2759-2761&publication_year=1992&author=Ikonen%2CE"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="32."><p class="c-article-references__text" id="ref-CR32">Svetina, C. et al. PRESTO, the on-line photon energy spectrometer at FERMI: design, features and commissioning results. <i>J. Synchrotron Rad.</i> <b>23</b>, 35–42 (2016).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1107/S1600577515021116" data-track-item_id="10.1107/S1600577515021116" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1107%2FS1600577515021116" aria-label="Article reference 32" data-doi="10.1107/S1600577515021116">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DC%2BC28XjtVyjuw%3D%3D" aria-label="CAS reference 32">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 32" href="http://scholar.google.com/scholar_lookup?&title=PRESTO%2C%20the%20on-line%20photon%20energy%20spectrometer%20at%20FERMI%3A%20design%2C%20features%20and%20commissioning%20results&journal=J.%20Synchrotron%20Rad.&doi=10.1107%2FS1600577515021116&volume=23&pages=35-42&publication_year=2016&author=Svetina%2CC"> Google Scholar</a> </p></li><li class="c-article-references__item js-c-reading-companion-references-item" data-counter="33."><p class="c-article-references__text" id="ref-CR33">Saldin, E., Schneidmiller, E. & Yurkov, M. Statistical properties of radiation from VUV and x-ray free electron laser. <i>Opt. Comm.</i> <b>148</b>, 383–403 (1998).</p><p class="c-article-references__links u-hide-print"><a data-track="click_references" rel="nofollow noopener" data-track-label="10.1016/S0030-4018(97)00670-6" data-track-item_id="10.1016/S0030-4018(97)00670-6" data-track-value="article reference" data-track-action="article reference" href="https://doi.org/10.1016%2FS0030-4018%2897%2900670-6" aria-label="Article reference 33" data-doi="10.1016/S0030-4018(97)00670-6">Article</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="ads reference" data-track-action="ads reference" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?link_type=ABSTRACT&bibcode=1998OptCo.148..383S" aria-label="ADS reference 33">ADS</a> <a data-track="click_references" rel="nofollow noopener" data-track-label="link" data-track-item_id="link" data-track-value="cas reference" data-track-action="cas reference" href="/articles/cas-redirect/1:CAS:528:DyaK1cXjslOnur8%3D" aria-label="CAS reference 33">CAS</a> <a data-track="click_references" data-track-action="google scholar reference" data-track-value="google scholar reference" data-track-label="link" data-track-item_id="link" rel="nofollow noopener" aria-label="Google Scholar reference 33" href="http://scholar.google.com/scholar_lookup?&title=Statistical%20properties%20of%20radiation%20from%20VUV%20and%20x-ray%20free%20electron%20laser&journal=Opt.%20Comm.&doi=10.1016%2FS0030-4018%2897%2900670-6&volume=148&pages=383-403&publication_year=1998&author=Saldin%2CE&author=Schneidmiller%2CE&author=Yurkov%2CM"> Google Scholar</a> </p></li></ol><p class="c-article-references__download u-hide-print"><a data-track="click" data-track-action="download citation references" data-track-label="link" rel="nofollow" href="https://citation-needed.springer.com/v2/references/10.1038/s41467-018-06743-8?format=refman&flavour=references">Download references<svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-download-medium"></use></svg></a></p></div></div></div></section></div><section data-title="Acknowledgements"><div class="c-article-section" id="Ack1-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Ack1">Acknowledgements</h2><div class="c-article-section__content" id="Ack1-content"><p>We thank the whole staff of FERMI for their support and excellent operation of the facility as well as for the fruitful discussions during this experiment; especially we are thankful to G. Penco and G. De Ninno from the FERMI facility. We acknowledge E. Weckert for helpful discussions and support of the project as well as fruitful discussions with F. Kärtner and careful reading of the manuscript by Yu. N. Obukhov and T. Laarmann.</p></div></div></section><section aria-labelledby="author-information" data-title="Author information"><div class="c-article-section" id="author-information-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="author-information">Author information</h2><div class="c-article-section__content" id="author-information-content"><span class="c-article-author-information__subtitle u-visually-hidden" id="author-notes">Author notes</span><ol class="c-article-author-information__list"><li class="c-article-author-information__item" id="nAff2"><p class="c-article-author-information__authors-list">Oleg Yu. Gorobtsov</p><p class="js-present-address">Present address: Department of Physics, University of Hamburg and Center for Free Electron Laser Science, Luruper Chausse 149, D-22761, Hamburg, Germany</p></li><li class="c-article-author-information__item" id="nAff5"><p class="c-article-author-information__authors-list">Petr Skopintsev</p><p class="js-present-address">Present address: National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe shosse 31, 115409, Moscow, Russia</p></li></ol><h3 class="c-article__sub-heading" id="affiliations">Authors and Affiliations</h3><ol class="c-article-author-affiliation__list"><li id="Aff1"><p class="c-article-author-affiliation__address">Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607, Hamburg, Germany</p><p class="c-article-author-affiliation__authors-list">Oleg Yu. Gorobtsov, Petr Skopintsev, Sergey Lazarev, Ivan A. Zaluzhnyy, Wilfried Wurth & Ivan A. Vartanyants</p></li><li id="Aff2"><p class="c-article-author-affiliation__address">Department of Physics, University of Hamburg and Center for Free Electron Laser Science, Luruper Chausse 149, D-22761, Hamburg, Germany</p><p class="c-article-author-affiliation__authors-list">Giuseppe Mercurio & Wilfried Wurth</p></li><li id="Aff3"><p class="c-article-author-affiliation__address">Elettra-Sincrotrone Trieste, 34149, Basovizza (Trieste), Italy</p><p class="c-article-author-affiliation__authors-list">Flavio Capotondi, Miltcho B. Danailov, Michele Manfredda, Emanuele Pedersoli, Luca Giannessi, Maya Kiskinova & Kevin C. Prince</p></li><li id="Aff4"><p class="c-article-author-affiliation__address">National Research Tomsk Polytechnic University (TPU), pr. Lenina 30, 634050, Tomsk, Russia</p><p class="c-article-author-affiliation__authors-list">Sergey Lazarev</p></li><li id="Aff5"><p class="c-article-author-affiliation__address">National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Kashirskoe shosse 31, 115409, Moscow, Russia</p><p class="c-article-author-affiliation__authors-list">Ivan A. Zaluzhnyy & Ivan A. Vartanyants</p></li><li id="Aff6"><p class="c-article-author-affiliation__address">CNR- IOM Istituto Officina dei Materiali, 34149, Trieste, Italy</p><p class="c-article-author-affiliation__authors-list">Martina Dell’Angela</p></li><li id="Aff7"><p class="c-article-author-affiliation__address">ENEA C.R. Frascati, Via E. Fermi 45, 00044, Frascati, Rome, Italy</p><p class="c-article-author-affiliation__authors-list">Luca Giannessi</p></li><li id="Aff8"><p class="c-article-author-affiliation__address">Molecular Model Discovery Laboratory, Department of Chemistry and Biotechnology, School of Science Swinburne University of Technology, Melbourne, VIC, 3122, Australia</p><p class="c-article-author-affiliation__authors-list">Kevin C. Prince</p></li><li id="Aff9"><p class="c-article-author-affiliation__address">Department of Materials Science and Engineering, Cornell University, Ithaca, NY, 14850, USA</p><p class="c-article-author-affiliation__authors-list">Oleg Yu. Gorobtsov</p></li><li id="Aff10"><p class="c-article-author-affiliation__address">European XFEL GmbH, Holzkoppel 4, D-22869, Schenefeld, Germany</p><p class="c-article-author-affiliation__authors-list">Giuseppe Mercurio</p></li><li id="Aff11"><p class="c-article-author-affiliation__address">Laboratory for Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institute, PSI Aarebrucke, 5232, Villigen, Switzerland</p><p class="c-article-author-affiliation__authors-list">Petr Skopintsev</p></li><li id="Aff12"><p class="c-article-author-affiliation__address">Department of Physics, University of California San Diego, La Jolla CA, 92093, USA</p><p class="c-article-author-affiliation__authors-list">Ivan A. Zaluzhnyy</p></li></ol><div class="u-js-hide u-hide-print" data-test="author-info"><span class="c-article__sub-heading">Authors</span><ol class="c-article-authors-search u-list-reset"><li id="auth-Oleg_Yu_-Gorobtsov-Aff1-Aff9"><span class="c-article-authors-search__title u-h3 js-search-name">Oleg Yu. Gorobtsov</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Oleg%20Yu.%20Gorobtsov" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Oleg%20Yu.%20Gorobtsov" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Oleg%20Yu.%20Gorobtsov%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Giuseppe-Mercurio-Aff2-Aff10"><span class="c-article-authors-search__title u-h3 js-search-name">Giuseppe Mercurio</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Giuseppe%20Mercurio" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Giuseppe%20Mercurio" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Giuseppe%20Mercurio%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Flavio-Capotondi-Aff3"><span class="c-article-authors-search__title u-h3 js-search-name">Flavio Capotondi</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Flavio%20Capotondi" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Flavio%20Capotondi" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Flavio%20Capotondi%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Petr-Skopintsev-Aff1-Aff11"><span class="c-article-authors-search__title u-h3 js-search-name">Petr Skopintsev</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Petr%20Skopintsev" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Petr%20Skopintsev" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Petr%20Skopintsev%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Sergey-Lazarev-Aff1-Aff4"><span class="c-article-authors-search__title u-h3 js-search-name">Sergey Lazarev</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Sergey%20Lazarev" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Sergey%20Lazarev" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Sergey%20Lazarev%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Ivan_A_-Zaluzhnyy-Aff1-Aff5-Aff12"><span class="c-article-authors-search__title u-h3 js-search-name">Ivan A. Zaluzhnyy</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Ivan%20A.%20Zaluzhnyy" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Ivan%20A.%20Zaluzhnyy" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Ivan%20A.%20Zaluzhnyy%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Miltcho_B_-Danailov-Aff3"><span class="c-article-authors-search__title u-h3 js-search-name">Miltcho B. Danailov</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Miltcho%20B.%20Danailov" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Miltcho%20B.%20Danailov" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Miltcho%20B.%20Danailov%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Martina-Dell_Angela-Aff6"><span class="c-article-authors-search__title u-h3 js-search-name">Martina Dell’Angela</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Martina%20Dell%E2%80%99Angela" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Martina%20Dell%E2%80%99Angela" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Martina%20Dell%E2%80%99Angela%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Michele-Manfredda-Aff3"><span class="c-article-authors-search__title u-h3 js-search-name">Michele Manfredda</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Michele%20Manfredda" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Michele%20Manfredda" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Michele%20Manfredda%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Emanuele-Pedersoli-Aff3"><span class="c-article-authors-search__title u-h3 js-search-name">Emanuele Pedersoli</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Emanuele%20Pedersoli" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Emanuele%20Pedersoli" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Emanuele%20Pedersoli%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Luca-Giannessi-Aff3-Aff7"><span class="c-article-authors-search__title u-h3 js-search-name">Luca Giannessi</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Luca%20Giannessi" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Luca%20Giannessi" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Luca%20Giannessi%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Maya-Kiskinova-Aff3"><span class="c-article-authors-search__title u-h3 js-search-name">Maya Kiskinova</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Maya%20Kiskinova" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Maya%20Kiskinova" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Maya%20Kiskinova%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Kevin_C_-Prince-Aff3-Aff8"><span class="c-article-authors-search__title u-h3 js-search-name">Kevin C. Prince</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Kevin%20C.%20Prince" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Kevin%20C.%20Prince" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Kevin%20C.%20Prince%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Wilfried-Wurth-Aff1-Aff2"><span class="c-article-authors-search__title u-h3 js-search-name">Wilfried Wurth</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Wilfried%20Wurth" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Wilfried%20Wurth" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Wilfried%20Wurth%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li><li id="auth-Ivan_A_-Vartanyants-Aff1-Aff5"><span class="c-article-authors-search__title u-h3 js-search-name">Ivan A. Vartanyants</span><div class="c-article-authors-search__list"><div class="c-article-authors-search__item c-article-authors-search__list-item--left"><a href="/search?author=Ivan%20A.%20Vartanyants" class="c-article-button" data-track="click" data-track-action="author link - publication" data-track-label="link" rel="nofollow">View author publications</a></div><div class="c-article-authors-search__item c-article-authors-search__list-item--right"><p class="search-in-title-js c-article-authors-search__text">You can also search for this author in <span class="c-article-identifiers"><a class="c-article-identifiers__item" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Ivan%20A.%20Vartanyants" data-track="click" data-track-action="author link - pubmed" data-track-label="link" rel="nofollow">PubMed</a><span class="u-hide"> </span><a class="c-article-identifiers__item" href="http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Ivan%20A.%20Vartanyants%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en" data-track="click" data-track-action="author link - scholar" data-track-label="link" rel="nofollow">Google Scholar</a></span></p></div></div></li></ol></div><h3 class="c-article__sub-heading" id="contributions">Contributions</h3><p>I.A.V., W.W., K.C.P. and M.K. conceived the experiment and coordinated the experimental efforts. L.G. planned FERMI FEL-2 operation. M.K., F.C., M.M. and E.P. prepared the DiProI end-station for measurements. O.Yu.G., G.M., F.C., P.S., S.L., I.Z., M.D., M.D.‘A, M.M., E.P., M.K., K.C.P., W.W. and I.A.V. performed the measurements. O.Yu.G. and P.S. analysed the data. O.Yu.G, I.A.V., L.G. and K.C.P. wrote the manuscript with contributions and improvements from all authors. All authors read and discussed the manuscript.</p><h3 class="c-article__sub-heading" id="corresponding-author">Corresponding author</h3><p id="corresponding-author-list">Correspondence to <a id="corresp-c1" href="mailto:ivan.vartaniants@desy.de">Ivan A. Vartanyants</a>.</p></div></div></section><section data-title="Ethics declarations"><div class="c-article-section" id="ethics-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="ethics">Ethics declarations</h2><div class="c-article-section__content" id="ethics-content"> <h3 class="c-article__sub-heading" id="FPar1">Competing interests</h3> <p>The authors declare no competing interests.</p> </div></div></section><section data-title="Additional information"><div class="c-article-section" id="additional-information-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="additional-information">Additional information</h2><div class="c-article-section__content" id="additional-information-content"><p><b>Publisher's note:</b> Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.</p></div></div></section><section data-title="Electronic supplementary material"><div class="c-article-section" id="Sec10-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="Sec10">Electronic supplementary material</h2><div class="c-article-section__content" id="Sec10-content"><div data-test="supplementary-info"><div id="figshareContainer" class="c-article-figshare-container" data-test="figshare-container"></div><div class="c-article-supplementary__item" data-test="supp-item" id="MOESM1"><h3 class="c-article-supplementary__title u-h3"><a class="print-link" data-track="click" data-track-action="view supplementary info" data-test="supp-info-link" data-track-label="supplementary information" href="https://static-content.springer.com/esm/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_MOESM1_ESM.pdf" data-supp-info-image="">Supplementary Information</a></h3></div><div class="c-article-supplementary__item" data-test="supp-item" id="MOESM2"><h3 class="c-article-supplementary__title u-h3"><a class="print-link" data-track="click" data-track-action="view supplementary info" data-test="supp-info-link" data-track-label="peer review file" href="https://static-content.springer.com/esm/art%3A10.1038%2Fs41467-018-06743-8/MediaObjects/41467_2018_6743_MOESM2_ESM.pdf" data-supp-info-image="">Peer Review File</a></h3></div></div></div></div></section><section data-title="Rights and permissions"><div class="c-article-section" id="rightslink-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="rightslink">Rights and permissions</h2><div class="c-article-section__content" id="rightslink-content"> <p><b>Open Access</b> This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit <a href="http://creativecommons.org/licenses/by/4.0/" rel="license">http://creativecommons.org/licenses/by/4.0/</a>.</p> <p class="c-article-rights"><a data-track="click" data-track-action="view rights and permissions" data-track-label="link" href="https://s100.copyright.com/AppDispatchServlet?title=Seeded%20X-ray%20free-electron%20laser%20generating%20radiation%20with%20laser%20statistical%20properties&author=Oleg%20Yu.%20Gorobtsov%20et%20al&contentID=10.1038%2Fs41467-018-06743-8&copyright=The%20Author%28s%29&publication=2041-1723&publicationDate=2018-10-29&publisherName=SpringerNature&orderBeanReset=true&oa=CC%20BY">Reprints and permissions</a></p></div></div></section><section aria-labelledby="article-info" data-title="About this article"><div class="c-article-section" id="article-info-section"><h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="article-info">About this article</h2><div class="c-article-section__content" id="article-info-content"><div class="c-bibliographic-information"><div class="u-hide-print c-bibliographic-information__column c-bibliographic-information__column--border"><a data-crossmark="10.1038/s41467-018-06743-8" target="_blank" rel="noopener" href="https://crossmark.crossref.org/dialog/?doi=10.1038/s41467-018-06743-8" data-track="click" data-track-action="Click Crossmark" data-track-label="link" data-test="crossmark"><img loading="lazy" width="57" height="81" alt="Check for updates. Verify currency and authenticity via CrossMark" src="data:image/svg+xml;base64,<svg height="81" width="57" xmlns="http://www.w3.org/2000/svg"><g fill="none" fill-rule="evenodd"><path d="m17.35 35.45 21.3-14.2v-17.03h-21.3" fill="#989898"/><path d="m38.65 35.45-21.3-14.2v-17.03h21.3" fill="#747474"/><path d="m28 .5c-12.98 0-23.5 10.52-23.5 23.5s10.52 23.5 23.5 23.5 23.5-10.52 23.5-23.5c0-6.23-2.48-12.21-6.88-16.62-4.41-4.4-10.39-6.88-16.62-6.88zm0 41.25c-9.8 0-17.75-7.95-17.75-17.75s7.95-17.75 17.75-17.75 17.75 7.95 17.75 17.75c0 4.71-1.87 9.22-5.2 12.55s-7.84 5.2-12.55 5.2z" fill="#535353"/><path d="m41 36c-5.81 6.23-15.23 7.45-22.43 2.9-7.21-4.55-10.16-13.57-7.03-21.5l-4.92-3.11c-4.95 10.7-1.19 23.42 8.78 29.71 9.97 6.3 23.07 4.22 30.6-4.86z" fill="#9c9c9c"/><path d="m.2 58.45c0-.75.11-1.42.33-2.01s.52-1.09.91-1.5c.38-.41.83-.73 1.34-.94.51-.22 1.06-.32 1.65-.32.56 0 1.06.11 1.51.35.44.23.81.5 1.1.81l-.91 1.01c-.24-.24-.49-.42-.75-.56-.27-.13-.58-.2-.93-.2-.39 0-.73.08-1.05.23-.31.16-.58.37-.81.66-.23.28-.41.63-.53 1.04-.13.41-.19.88-.19 1.39 0 1.04.23 1.86.68 2.46.45.59 1.06.88 1.84.88.41 0 .77-.07 1.07-.23s.59-.39.85-.68l.91 1c-.38.43-.8.76-1.28.99-.47.22-1 .34-1.58.34-.59 0-1.13-.1-1.64-.31-.5-.2-.94-.51-1.31-.91-.38-.4-.67-.9-.88-1.48-.22-.59-.33-1.26-.33-2.02zm8.4-5.33h1.61v2.54l-.05 1.33c.29-.27.61-.51.96-.72s.76-.31 1.24-.31c.73 0 1.27.23 1.61.71.33.47.5 1.14.5 2.02v4.31h-1.61v-4.1c0-.57-.08-.97-.25-1.21-.17-.23-.45-.35-.83-.35-.3 0-.56.08-.79.22-.23.15-.49.36-.78.64v4.8h-1.61zm7.37 6.45c0-.56.09-1.06.26-1.51.18-.45.42-.83.71-1.14.29-.3.63-.54 1.01-.71.39-.17.78-.25 1.18-.25.47 0 .88.08 1.23.24.36.16.65.38.89.67s.42.63.54 1.03c.12.41.18.84.18 1.32 0 .32-.02.57-.07.76h-4.36c.07.62.29 1.1.65 1.44.36.33.82.5 1.38.5.29 0 .57-.04.83-.13s.51-.21.76-.37l.55 1.01c-.33.21-.69.39-1.09.53-.41.14-.83.21-1.26.21-.48 0-.92-.08-1.34-.25-.41-.16-.76-.4-1.07-.7-.31-.31-.55-.69-.72-1.13-.18-.44-.26-.95-.26-1.52zm4.6-.62c0-.55-.11-.98-.34-1.28-.23-.31-.58-.47-1.06-.47-.41 0-.77.15-1.07.45-.31.29-.5.73-.58 1.3zm2.5.62c0-.57.09-1.08.28-1.53.18-.44.43-.82.75-1.13s.69-.54 1.1-.71c.42-.16.85-.24 1.31-.24.45 0 .84.08 1.17.23s.61.34.85.57l-.77 1.02c-.19-.16-.38-.28-.56-.37-.19-.09-.39-.14-.61-.14-.56 0-1.01.21-1.35.63-.35.41-.52.97-.52 1.67 0 .69.17 1.24.51 1.66.34.41.78.62 1.32.62.28 0 .54-.06.78-.17.24-.12.45-.26.64-.42l.67 1.03c-.33.29-.69.51-1.08.65-.39.15-.78.23-1.18.23-.46 0-.9-.08-1.31-.24-.4-.16-.75-.39-1.05-.7s-.53-.69-.7-1.13c-.17-.45-.25-.96-.25-1.53zm6.91-6.45h1.58v6.17h.05l2.54-3.16h1.77l-2.35 2.8 2.59 4.07h-1.75l-1.77-2.98-1.08 1.23v1.75h-1.58zm13.69 1.27c-.25-.11-.5-.17-.75-.17-.58 0-.87.39-.87 1.16v.75h1.34v1.27h-1.34v5.6h-1.61v-5.6h-.92v-1.2l.92-.07v-.72c0-.35.04-.68.13-.98.08-.31.21-.57.4-.79s.42-.39.71-.51c.28-.12.63-.18 1.04-.18.24 0 .48.02.69.07.22.05.41.1.57.17zm.48 5.18c0-.57.09-1.08.27-1.53.17-.44.41-.82.72-1.13.3-.31.65-.54 1.04-.71.39-.16.8-.24 1.23-.24s.84.08 1.24.24c.4.17.74.4 1.04.71s.54.69.72 1.13c.19.45.28.96.28 1.53s-.09 1.08-.28 1.53c-.18.44-.42.82-.72 1.13s-.64.54-1.04.7-.81.24-1.24.24-.84-.08-1.23-.24-.74-.39-1.04-.7c-.31-.31-.55-.69-.72-1.13-.18-.45-.27-.96-.27-1.53zm1.65 0c0 .69.14 1.24.43 1.66.28.41.68.62 1.18.62.51 0 .9-.21 1.19-.62.29-.42.44-.97.44-1.66 0-.7-.15-1.26-.44-1.67-.29-.42-.68-.63-1.19-.63-.5 0-.9.21-1.18.63-.29.41-.43.97-.43 1.67zm6.48-3.44h1.33l.12 1.21h.05c.24-.44.54-.79.88-1.02.35-.24.7-.36 1.07-.36.32 0 .59.05.78.14l-.28 1.4-.33-.09c-.11-.01-.23-.02-.38-.02-.27 0-.56.1-.86.31s-.55.58-.77 1.1v4.2h-1.61zm-47.87 15h1.61v4.1c0 .57.08.97.25 1.2.17.24.44.35.81.35.3 0 .57-.07.8-.22.22-.15.47-.39.73-.73v-4.7h1.61v6.87h-1.32l-.12-1.01h-.04c-.3.36-.63.64-.98.86-.35.21-.76.32-1.24.32-.73 0-1.27-.24-1.61-.71-.33-.47-.5-1.14-.5-2.02zm9.46 7.43v2.16h-1.61v-9.59h1.33l.12.72h.05c.29-.24.61-.45.97-.63.35-.17.72-.26 1.1-.26.43 0 .81.08 1.15.24.33.17.61.4.84.71.24.31.41.68.53 1.11.13.42.19.91.19 1.44 0 .59-.09 1.11-.25 1.57-.16.47-.38.85-.65 1.16-.27.32-.58.56-.94.73-.35.16-.72.25-1.1.25-.3 0-.6-.07-.9-.2s-.59-.31-.87-.56zm0-2.3c.26.22.5.37.73.45.24.09.46.13.66.13.46 0 .84-.2 1.15-.6.31-.39.46-.98.46-1.77 0-.69-.12-1.22-.35-1.61-.23-.38-.61-.57-1.13-.57-.49 0-.99.26-1.52.77zm5.87-1.69c0-.56.08-1.06.25-1.51.16-.45.37-.83.65-1.14.27-.3.58-.54.93-.71s.71-.25 1.08-.25c.39 0 .73.07 1 .2.27.14.54.32.81.55l-.06-1.1v-2.49h1.61v9.88h-1.33l-.11-.74h-.06c-.25.25-.54.46-.88.64-.33.18-.69.27-1.06.27-.87 0-1.56-.32-2.07-.95s-.76-1.51-.76-2.65zm1.67-.01c0 .74.13 1.31.4 1.7.26.38.65.58 1.15.58.51 0 .99-.26 1.44-.77v-3.21c-.24-.21-.48-.36-.7-.45-.23-.08-.46-.12-.7-.12-.45 0-.82.19-1.13.59-.31.39-.46.95-.46 1.68zm6.35 1.59c0-.73.32-1.3.97-1.71.64-.4 1.67-.68 3.08-.84 0-.17-.02-.34-.07-.51-.05-.16-.12-.3-.22-.43s-.22-.22-.38-.3c-.15-.06-.34-.1-.58-.1-.34 0-.68.07-1 .2s-.63.29-.93.47l-.59-1.08c.39-.24.81-.45 1.28-.63.47-.17.99-.26 1.54-.26.86 0 1.51.25 1.93.76s.63 1.25.63 2.21v4.07h-1.32l-.12-.76h-.05c-.3.27-.63.48-.98.66s-.73.27-1.14.27c-.61 0-1.1-.19-1.48-.56-.38-.36-.57-.85-.57-1.46zm1.57-.12c0 .3.09.53.27.67.19.14.42.21.71.21.28 0 .54-.07.77-.2s.48-.31.73-.56v-1.54c-.47.06-.86.13-1.18.23-.31.09-.57.19-.76.31s-.33.25-.41.4c-.09.15-.13.31-.13.48zm6.29-3.63h-.98v-1.2l1.06-.07.2-1.88h1.34v1.88h1.75v1.27h-1.75v3.28c0 .8.32 1.2.97 1.2.12 0 .24-.01.37-.04.12-.03.24-.07.34-.11l.28 1.19c-.19.06-.4.12-.64.17-.23.05-.49.08-.76.08-.4 0-.74-.06-1.02-.18-.27-.13-.49-.3-.67-.52-.17-.21-.3-.48-.37-.78-.08-.3-.12-.64-.12-1.01zm4.36 2.17c0-.56.09-1.06.27-1.51s.41-.83.71-1.14c.29-.3.63-.54 1.01-.71.39-.17.78-.25 1.18-.25.47 0 .88.08 1.23.24.36.16.65.38.89.67s.42.63.54 1.03c.12.41.18.84.18 1.32 0 .32-.02.57-.07.76h-4.37c.08.62.29 1.1.65 1.44.36.33.82.5 1.38.5.3 0 .58-.04.84-.13.25-.09.51-.21.76-.37l.54 1.01c-.32.21-.69.39-1.09.53s-.82.21-1.26.21c-.47 0-.92-.08-1.33-.25-.41-.16-.77-.4-1.08-.7-.3-.31-.54-.69-.72-1.13-.17-.44-.26-.95-.26-1.52zm4.61-.62c0-.55-.11-.98-.34-1.28-.23-.31-.58-.47-1.06-.47-.41 0-.77.15-1.08.45-.31.29-.5.73-.57 1.3zm3.01 2.23c.31.24.61.43.92.57.3.13.63.2.98.2.38 0 .65-.08.83-.23s.27-.35.27-.6c0-.14-.05-.26-.13-.37-.08-.1-.2-.2-.34-.28-.14-.09-.29-.16-.47-.23l-.53-.22c-.23-.09-.46-.18-.69-.3-.23-.11-.44-.24-.62-.4s-.33-.35-.45-.55c-.12-.21-.18-.46-.18-.75 0-.61.23-1.1.68-1.49.44-.38 1.06-.57 1.83-.57.48 0 .91.08 1.29.25s.71.36.99.57l-.74.98c-.24-.17-.49-.32-.73-.42-.25-.11-.51-.16-.78-.16-.35 0-.6.07-.76.21-.17.15-.25.33-.25.54 0 .14.04.26.12.36s.18.18.31.26c.14.07.29.14.46.21l.54.19c.23.09.47.18.7.29s.44.24.64.4c.19.16.34.35.46.58.11.23.17.5.17.82 0 .3-.06.58-.17.83-.12.26-.29.48-.51.68-.23.19-.51.34-.84.45-.34.11-.72.17-1.15.17-.48 0-.95-.09-1.41-.27-.46-.19-.86-.41-1.2-.68z" fill="#535353"/></g></svg>"></a></div><div class="c-bibliographic-information__column"><h3 class="c-article__sub-heading" id="citeas">Cite this article</h3><p class="c-bibliographic-information__citation">Gorobtsov, O.Y., Mercurio, G., Capotondi, F. <i>et al.</i> Seeded X-ray free-electron laser generating radiation with laser statistical properties. <i>Nat Commun</i> <b>9</b>, 4498 (2018). https://doi.org/10.1038/s41467-018-06743-8</p><p class="c-bibliographic-information__download-citation u-hide-print"><a data-test="citation-link" data-track="click" data-track-action="download article citation" data-track-label="link" data-track-external="" rel="nofollow" href="https://citation-needed.springer.com/v2/references/10.1038/s41467-018-06743-8?format=refman&flavour=citation">Download citation<svg width="16" height="16" focusable="false" role="img" aria-hidden="true" class="u-icon"><use xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="#icon-eds-i-download-medium"></use></svg></a></p><ul class="c-bibliographic-information__list" data-test="publication-history"><li class="c-bibliographic-information__list-item"><p>Received<span class="u-hide">: </span><span class="c-bibliographic-information__value"><time datetime="2018-07-06">06 July 2018</time></span></p></li><li class="c-bibliographic-information__list-item"><p>Accepted<span class="u-hide">: </span><span class="c-bibliographic-information__value"><time datetime="2018-09-13">13 September 2018</time></span></p></li><li class="c-bibliographic-information__list-item"><p>Published<span class="u-hide">: </span><span class="c-bibliographic-information__value"><time datetime="2018-10-29">29 October 2018</time></span></p></li><li class="c-bibliographic-information__list-item c-bibliographic-information__list-item--full-width"><p><abbr title="Digital Object Identifier">DOI</abbr><span class="u-hide">: </span><span class="c-bibliographic-information__value">https://doi.org/10.1038/s41467-018-06743-8</span></p></li></ul><div data-component="share-box"><div class="c-article-share-box u-display-none" hidden=""><h3 class="c-article__sub-heading">Share this article</h3><p class="c-article-share-box__description">Anyone you share the following link with will be able to read this content:</p><button class="js-get-share-url c-article-share-box__button" type="button" id="get-share-url" data-track="click" data-track-label="button" data-track-external="" data-track-action="get shareable link">Get shareable link</button><div class="js-no-share-url-container u-display-none" hidden=""><p class="js-c-article-share-box__no-sharelink-info c-article-share-box__no-sharelink-info">Sorry, a shareable link is not currently available for this article.</p></div><div class="js-share-url-container u-display-none" hidden=""><p class="js-share-url c-article-share-box__only-read-input" id="share-url" data-track="click" data-track-label="button" data-track-action="select share url"></p><button class="js-copy-share-url c-article-share-box__button--link-like" type="button" id="copy-share-url" data-track="click" data-track-label="button" data-track-action="copy share url" data-track-external="">Copy to clipboard</button></div><p class="js-c-article-share-box__additional-info c-article-share-box__additional-info"> Provided by the Springer Nature SharedIt content-sharing initiative </p></div></div><div data-component="article-info-list"></div></div></div></div></div></section> </div> <section> <div class="c-article-section js-article-section" id="further-reading-section" data-test="further-reading-section"> <h2 class="c-article-section__title js-section-title js-c-reading-companion-sections-item" id="further-reading">This article is cited by</h2> <div class="c-article-section__content js-collapsible-section" id="further-reading-content"> <ul class="c-article-further-reading__list" id="further-reading-list"> <li class="c-article-further-reading__item js-ref-item"> <h3 class="c-article-further-reading__title" data-test="article-title"> <a class="print-link" data-track="click" data-track-action="view further reading article" data-track-label="link:Prospects for free-electron lasers powered by plasma-wakefield-accelerated beams" href="https://doi.org/10.1038/s41566-024-01474-3"> Prospects for free-electron lasers powered by plasma-wakefield-accelerated beams </a> </h3> <ul data-test="author-list" class="c-author-list c-author-list--compact c-author-list--truncated u-sans-serif u-mb-4 u-mt-auto"> <li>M. Galletti</li><li>R. Assmann</li><li>W. Wang</li> </ul> <p class="c-article-further-reading__journal-title"><i>Nature Photonics</i> (2024)</p> </li> <li class="c-article-further-reading__item js-ref-item"> <h3 class="c-article-further-reading__title" data-test="article-title"> <a class="print-link" data-track="click" data-track-action="view further reading article" data-track-label="link:Progress and prospects in nonlinear extreme-ultraviolet and X-ray optics and spectroscopy" href="https://doi.org/10.1038/s42254-023-00643-7"> Progress and prospects in nonlinear extreme-ultraviolet and X-ray optics and spectroscopy </a> </h3> <ul data-test="author-list" class="c-author-list c-author-list--compact c-author-list--truncated u-sans-serif u-mb-4 u-mt-auto"> <li>Majed Chergui</li><li>Martin Beye</li><li>Claudio Masciovecchio</li> </ul> <p class="c-article-further-reading__journal-title"><i>Nature Reviews Physics</i> (2023)</p> </li> <li class="c-article-further-reading__item js-ref-item"> <h3 class="c-article-further-reading__title" data-test="article-title"> <a class="print-link" data-track="click" data-track-action="view further reading article" data-track-label="link:Seeded free-electron laser driven by a compact laser plasma accelerator" href="https://doi.org/10.1038/s41566-022-01104-w"> Seeded free-electron laser driven by a compact laser plasma accelerator </a> </h3> <ul data-test="author-list" class="c-author-list c-author-list--compact c-author-list--truncated u-sans-serif u-mb-4 u-mt-auto"> <li>Marie Labat</li><li>Jurjen Couperus Cabadağ</li><li>Marie-Emmanuelle Couprie</li> </ul> <p class="c-article-further-reading__journal-title"><i>Nature Photonics</i> (2023)</p> </li> <li class="c-article-further-reading__item js-ref-item"> <h3 class="c-article-further-reading__title" data-test="article-title"> <a class="print-link" data-track="click" data-track-action="view further reading article" data-track-label="link:Transient measurement of phononic states with covariance-based stochastic spectroscopy" href="https://doi.org/10.1038/s41377-022-00727-6"> Transient measurement of phononic states with covariance-based stochastic spectroscopy </a> </h3> <ul data-test="author-list" class="c-author-list c-author-list--compact c-author-list--truncated u-sans-serif u-mb-4 u-mt-auto"> <li>Giorgia Sparapassi</li><li>Stefano M. Cavaletto</li><li>Daniele Fausti</li> </ul> <p class="c-article-further-reading__journal-title"><i>Light: Science & Applications</i> (2022)</p> </li> <li class="c-article-further-reading__item js-ref-item"> <h3 class="c-article-further-reading__title" data-test="article-title"> <a class="print-link" data-track="click" data-track-action="view further reading article" data-track-label="link:Transient gratings with X-rays" href="https://doi.org/10.1038/s41566-021-00837-4"> Transient gratings with X-rays </a> </h3> <ul data-test="author-list" class="c-author-list c-author-list--compact u-sans-serif u-mb-4 u-mt-auto"> <li>Martin Beye</li> </ul> <p class="c-article-further-reading__journal-title"><i>Nature Photonics</i> (2021)</p> </li> </ul> </div> </div> </section> </div> </article> </main> <aside class="c-article-extras u-hide-print" aria-label="Article navigation" data-component-reading-companion data-container-type="reading-companion" data-track-component="reading companion"> <div class="js-context-bar-sticky-point-desktop" data-track-context="reading companion"> <div class="c-pdf-download u-clear-both js-pdf-download"> <a href="/articles/s41467-018-06743-8.pdf" class="u-button u-button--full-width u-button--primary u-justify-content-space-between c-pdf-download__link" data-article-pdf="true" data-readcube-pdf-url="true" data-test="download-pdf" data-draft-ignore="true" data-track="content_download" data-track-type="article pdf download" data-track-action="download pdf" data-track-label="link" data-track-external download> <span class="c-pdf-download__text">Download PDF</span> <svg aria-hidden="true" focusable="false" width="16" height="16" class="u-icon"><use xlink:href="#icon-download"/></svg> </a> </div> </div> <div class="c-article-associated-content__container"> <section> <h2 class="c-article-associated-content__title u-mb-24">Associated content</h2> <div class="c-article-associated-content__collection collection u-mb-24"> <section> <p class="c-article-associated-content__collection-label u-sans-serif u-text-bold u-mb-8">Collection</p> <h3 class="c-article-associated-content__collection-title u-h3 u-mb-8"> <a href="https://www.nature.com/collections/cssxtbybyl" class="u-link-inherit" data-track="click" data-track-action="view collection" data-track-category="associated content" data-track-label="collection" data-test="collection-link">Free-Electron Lasers</a> </h3> </section> </div> </section> </div> <script> window.dataLayer = window.dataLayer || []; window.dataLayer[0] = window.dataLayer[0] || {}; window.dataLayer[0].content = window.dataLayer[0].content || {}; window.dataLayer[0].content.associatedContentTypes = "collection"; window.dataLayer[0].content.collections = "cssxtbybyl"; </script> <div class="c-reading-companion"> <div class="c-reading-companion__sticky" data-component="reading-companion-sticky" data-test="reading-companion-sticky"> <div class="c-reading-companion__panel c-reading-companion__sections c-reading-companion__panel--active" id="tabpanel-sections"> <div class="u-lazy-ad-wrapper u-mt-16 u-hide" data-component-mpu> <div class="c-ad c-ad--300x250"> <div class="c-ad__inner"> <p class="c-ad__label">Advertisement</p> <div id="div-gpt-ad-right-2" class="div-gpt-ad advert medium-rectangle js-ad text-center hide-print grade-c-hide" data-ad-type="right" data-test="right-ad" data-pa11y-ignore data-gpt data-gpt-unitpath="/285/nature_communications/article" data-gpt-sizes="300x250" data-gpt-targeting="type=article;pos=right;artid=s41467-018-06743-8;doi=10.1038/s41467-018-06743-8;techmeta=124,132,145;subjmeta=1020,1087,1107,527,624,639;kwrd=Free-electron+lasers,Optical+spectroscopy"> <noscript> <a href="//pubads.g.doubleclick.net/gampad/jump?iu=/285/nature_communications/article&sz=300x250&c=-1596694158&t=pos%3Dright%26type%3Darticle%26artid%3Ds41467-018-06743-8%26doi%3D10.1038/s41467-018-06743-8%26techmeta%3D124,132,145%26subjmeta%3D1020,1087,1107,527,624,639%26kwrd%3DFree-electron+lasers,Optical+spectroscopy"> <img data-test="gpt-advert-fallback-img" src="//pubads.g.doubleclick.net/gampad/ad?iu=/285/nature_communications/article&sz=300x250&c=-1596694158&t=pos%3Dright%26type%3Darticle%26artid%3Ds41467-018-06743-8%26doi%3D10.1038/s41467-018-06743-8%26techmeta%3D124,132,145%26subjmeta%3D1020,1087,1107,527,624,639%26kwrd%3DFree-electron+lasers,Optical+spectroscopy" alt="Advertisement" width="300" height="250"></a> </noscript> </div> </div> </div> </div> </div> <div class="c-reading-companion__panel c-reading-companion__figures c-reading-companion__panel--full-width" id="tabpanel-figures"></div> <div class="c-reading-companion__panel c-reading-companion__references c-reading-companion__panel--full-width" id="tabpanel-references"></div> </div> </div> </aside> </div> <nav class="c-header__dropdown" aria-labelledby="Explore-content" data-test="Explore-content" id="explore" data-track-component="nature-150-split-header"> <div class="c-header__container"> <h2 id="Explore-content" class="c-header__heading c-header__heading--js-hide">Explore content</h2> <ul class="c-header__list c-header__list--js-stack"> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/research-articles" data-track="click" data-track-action="research articles" data-track-label="link" data-test="explore-nav-item"> Research articles </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/reviews-and-analysis" data-track="click" data-track-action="reviews & analysis" data-track-label="link" data-test="explore-nav-item"> Reviews & Analysis </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/news-and-comment" data-track="click" data-track-action="news & comment" data-track-label="link" data-test="explore-nav-item"> News & Comment </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/video" data-track="click" data-track-action="videos" data-track-label="link" data-test="explore-nav-item"> Videos </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/collections" data-track="click" data-track-action="collections" data-track-label="link" data-test="explore-nav-item"> Collections </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/browse-subjects" data-track="click" data-track-action="subjects" data-track-label="link" data-test="explore-nav-item"> Subjects </a> </li> </ul> <ul class="c-header__list c-header__list--js-stack"> <li class="c-header__item"> <a class="c-header__link" href="https://www.facebook.com/NatureCommunications" data-track="click" data-track-action="facebook" data-track-label="link">Follow us on Facebook </a> </li> <li class="c-header__item"> <a class="c-header__link" href="https://twitter.com/NatureComms" data-track="click" data-track-action="twitter" data-track-label="link">Follow us on Twitter </a> </li> <li class="c-header__item c-header__item--hide-lg"> <a class="c-header__link" href="https://www.nature.com/my-account/alerts/subscribe-journal?list-id=264" rel="nofollow" data-track="click" data-track-action="Sign up for alerts" data-track-external data-track-label="link (mobile dropdown)">Sign up for alerts<svg role="img" aria-hidden="true" focusable="false" height="18" viewBox="0 0 18 18" width="18" xmlns="http://www.w3.org/2000/svg"><path d="m4 10h2.5c.27614237 0 .5.2238576.5.5s-.22385763.5-.5.5h-3.08578644l-1.12132034 1.1213203c-.18753638.1875364-.29289322.4418903-.29289322.7071068v.1715729h14v-.1715729c0-.2652165-.1053568-.5195704-.2928932-.7071068l-1.7071068-1.7071067v-3.4142136c0-2.76142375-2.2385763-5-5-5-2.76142375 0-5 2.23857625-5 5zm3 4c0 1.1045695.8954305 2 2 2s2-.8954305 2-2zm-5 0c-.55228475 0-1-.4477153-1-1v-.1715729c0-.530433.21071368-1.0391408.58578644-1.4142135l1.41421356-1.4142136v-3c0-3.3137085 2.6862915-6 6-6s6 2.6862915 6 6v3l1.4142136 1.4142136c.3750727.3750727.5857864.8837805.5857864 1.4142135v.1715729c0 .5522847-.4477153 1-1 1h-4c0 1.6568542-1.3431458 3-3 3-1.65685425 0-3-1.3431458-3-3z" fill="#fff"/></svg> </a> </li> <li class="c-header__item c-header__item--hide-lg"> <a class="c-header__link" href="https://www.nature.com/ncomms.rss" data-track="click" data-track-action="rss feed" data-track-label="link"> <span>RSS feed</span> </a> </li> </ul> </div> </nav> <nav class="c-header__dropdown" aria-labelledby="About-the-journal" id="about-the-journal" data-test="about-the-journal" data-track-component="nature-150-split-header"> <div class="c-header__container"> <h2 id="About-the-journal" class="c-header__heading c-header__heading--js-hide">About the journal</h2> <ul class="c-header__list c-header__list--js-stack"> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/aims" data-track="click" data-track-action="aims & scope" data-track-label="link"> Aims & Scope </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/editors" data-track="click" data-track-action="editors" data-track-label="link"> Editors </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/journal-information" data-track="click" data-track-action="journal information" data-track-label="link"> Journal Information </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/open-access" data-track="click" data-track-action="open access fees and funding" data-track-label="link"> Open Access Fees and Funding </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/calls-for-papers" data-track="click" data-track-action="calls for papers" data-track-label="link"> Calls for Papers </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/editorial-values-statement" data-track="click" data-track-action="editorial values statement" data-track-label="link"> Editorial Values Statement </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/journal-impact" data-track="click" data-track-action="journal metrics" data-track-label="link"> Journal Metrics </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/editorshighlights" data-track="click" data-track-action="editors' highlights" data-track-label="link"> Editors' Highlights </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/contact" data-track="click" data-track-action="contact" data-track-label="link"> Contact </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/editorial-policies" data-track="click" data-track-action="editorial policies" data-track-label="link"> Editorial policies </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/top-articles" data-track="click" data-track-action="top articles" data-track-label="link"> Top Articles </a> </li> </ul> </div> </nav> <nav class="c-header__dropdown" aria-labelledby="Publish-with-us-label" id="publish-with-us" data-test="publish-with-us" data-track-component="nature-150-split-header"> <div class="c-header__container"> <h2 id="Publish-with-us-label" class="c-header__heading c-header__heading--js-hide">Publish with us</h2> <ul class="c-header__list c-header__list--js-stack"> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/submit" data-track="click" data-track-action="for authors" data-track-label="link"> For authors </a> </li> <li class="c-header__item"> <a class="c-header__link" href="/ncomms/for-reviewers" data-track="click" data-track-action="for reviewers" data-track-label="link"> For Reviewers </a> </li> <li class="c-header__item"> <a class="c-header__link" data-test="nature-author-services" data-track="nav_language_services" data-track-context="header publish with us dropdown menu" data-track-action="manuscript author services" data-track-label="link manuscript author services" href="https://authorservices.springernature.com/go/sn/?utm_source=For+Authors&utm_medium=Website_Nature&utm_campaign=Platform+Experimentation+2022&utm_id=PE2022"> Language editing services </a> </li> <li class="c-header__item c-header__item--keyline"> <a class="c-header__link" href="https://mts-ncomms.nature.com/" data-track="click_submit_manuscript" data-track-context="submit link in Nature header dropdown menu" data-track-action="submit manuscript" data-track-label="link (publish with us dropdown menu)" data-track-external data-gtm-criteo="submit-manuscript">Submit manuscript<svg role="img" aria-hidden="true" focusable="false" height="18" viewBox="0 0 18 18" width="18" xmlns="http://www.w3.org/2000/svg"><path d="m15 0c1.1045695 0 2 .8954305 2 2v5.5c0 .27614237-.2238576.5-.5.5s-.5-.22385763-.5-.5v-5.5c0-.51283584-.3860402-.93550716-.8833789-.99327227l-.1166211-.00672773h-9v3c0 1.1045695-.8954305 2-2 2h-3v10c0 .5128358.38604019.9355072.88337887.9932723l.11662113.0067277h7.5c.27614237 0 .5.2238576.5.5s-.22385763.5-.5.5h-7.5c-1.1045695 0-2-.8954305-2-2v-10.17157288c0-.53043297.21071368-1.0391408.58578644-1.41421356l3.82842712-3.82842712c.37507276-.37507276.88378059-.58578644 1.41421356-.58578644zm-.5442863 8.18867991 3.3545404 3.35454039c.2508994.2508994.2538696.6596433.0035959.909917-.2429543.2429542-.6561449.2462671-.9065387-.0089489l-2.2609825-2.3045251.0010427 7.2231989c0 .3569916-.2898381.6371378-.6473715.6371378-.3470771 0-.6473715-.2852563-.6473715-.6371378l-.0010428-7.2231995-2.2611222 2.3046654c-.2531661.2580415-.6562868.2592444-.9065605.0089707-.24295423-.2429542-.24865597-.6576651.0036132-.9099343l3.3546673-3.35466731c.2509089-.25090888.6612706-.25227691.9135302-.00001728zm-.9557137-3.18867991c.2761424 0 .5.22385763.5.5s-.2238576.5-.5.5h-6c-.27614237 0-.5-.22385763-.5-.5s.22385763-.5.5-.5zm-8.5-3.587-3.587 3.587h2.587c.55228475 0 1-.44771525 1-1zm8.5 1.587c.2761424 0 .5.22385763.5.5s-.2238576.5-.5.5h-6c-.27614237 0-.5-.22385763-.5-.5s.22385763-.5.5-.5z" fill="#fff"/></svg> </a> </li> </ul> </div> </nav> <div id="search-menu" class="c-header__dropdown c-header__dropdown--full-width" data-track-component="nature-150-split-header"> <div class="c-header__container"> <h2 class="c-header__visually-hidden">Search</h2> <form class="c-header__search-form" action="/search" method="get" role="search" autocomplete="off" data-test="inline-search"> <label class="c-header__heading" for="keywords">Search articles by subject, keyword or author</label> <div class="c-header__search-layout c-header__search-layout--max-width"> <div> <input type="text" required="" class="c-header__input" id="keywords" name="q" value=""> </div> <div class="c-header__search-layout"> <div> <label for="results-from" class="c-header__visually-hidden">Show results from</label> <select id="results-from" name="journal" class="c-header__select"> <option value="" selected>All journals</option> <option value="ncomms">This journal</option> </select> </div> <div> <button type="submit" class="c-header__search-button">Search</button> </div> </div> </div> </form> <div class="c-header__flush"> <a class="c-header__link" href="/search/advanced" data-track="click" data-track-action="advanced search" data-track-label="link"> Advanced search </a> </div> <h3 class="c-header__heading c-header__heading--keyline">Quick links</h3> <ul class="c-header__list"> <li><a class="c-header__link" href="/subjects" data-track="click" data-track-action="explore articles by subject" data-track-label="link">Explore articles by subject</a></li> <li><a class="c-header__link" href="/naturecareers" data-track="click" data-track-action="find a job" data-track-label="link">Find a job</a></li> <li><a class="c-header__link" href="/authors/index.html" data-track="click" data-track-action="guide to authors" data-track-label="link">Guide to authors</a></li> <li><a class="c-header__link" href="/authors/editorial_policies/" data-track="click" data-track-action="editorial policies" data-track-label="link">Editorial policies</a></li> </ul> </div> </div> <footer class="composite-layer" itemscope itemtype="http://schema.org/Periodical"> <meta itemprop="publisher" content="Springer Nature"> <div class="u-mt-16 u-mb-16"> <div class="u-container"> <div class="u-display-flex u-flex-wrap u-justify-content-space-between"> <p class="c-meta u-ma-0 u-flex-shrink"> <span class="c-meta__item"> Nature Communications (<i>Nat Commun</i>) </span> <span class="c-meta__item"> <abbr title="International Standard Serial Number">ISSN</abbr> <span itemprop="onlineIssn">2041-1723</span> (online) </span> </p> </div> </div> </div> <div class="c-footer"> <div class="u-hide-print" data-track-component="footer"> <h2 class="u-visually-hidden">nature.com sitemap</h2> <div class="c-footer__container"> <div class="c-footer__grid c-footer__group--separator"> <div class="c-footer__group"> <h3 class="c-footer__heading u-mt-0">About Nature Portfolio</h3> <ul class="c-footer__list"> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/npg_/company_info/index.html" data-track="click" data-track-action="about us" data-track-label="link">About us</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/npg_/press_room/press_releases.html" data-track="click" data-track-action="press releases" data-track-label="link">Press releases</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://press.nature.com/" data-track="click" data-track-action="press office" data-track-label="link">Press office</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://support.nature.com/support/home" data-track="click" data-track-action="contact us" data-track-label="link">Contact us</a></li> </ul> </div> <div class="c-footer__group"> <h3 class="c-footer__heading u-mt-0">Discover content</h3> <ul class="c-footer__list"> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/siteindex" data-track="click" data-track-action="journals a-z" data-track-label="link">Journals A-Z</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/subjects" data-track="click" data-track-action="article by subject" data-track-label="link">Articles by subject</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.protocols.io/" data-track="click" data-track-action="protocols.io" data-track-label="link">protocols.io</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.natureindex.com/" data-track="click" data-track-action="nature index" data-track-label="link">Nature Index</a></li> </ul> </div> <div class="c-footer__group"> <h3 class="c-footer__heading u-mt-0">Publishing policies</h3> <ul class="c-footer__list"> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/authors/editorial_policies" data-track="click" data-track-action="Nature portfolio policies" data-track-label="link">Nature portfolio policies</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/nature-research/open-access" data-track="click" data-track-action="open access" data-track-label="link">Open access</a></li> </ul> </div> <div class="c-footer__group"> <h3 class="c-footer__heading u-mt-0">Author & Researcher services</h3> <ul class="c-footer__list"> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/reprints" data-track="click" data-track-action="reprints and permissions" data-track-label="link">Reprints & permissions</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.springernature.com/gp/authors/research-data" data-track="click" data-track-action="data research service" data-track-label="link">Research data</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://authorservices.springernature.com/language-editing/" data-track="click" data-track-action="language editing" data-track-label="link">Language editing</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://authorservices.springernature.com/scientific-editing/" data-track="click" data-track-action="scientific editing" data-track-label="link">Scientific editing</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://masterclasses.nature.com/" data-track="click" data-track-action="nature masterclasses" data-track-label="link">Nature Masterclasses</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://solutions.springernature.com/" data-track="click" data-track-action="research solutions" data-track-label="link">Research Solutions</a></li> </ul> </div> <div class="c-footer__group"> <h3 class="c-footer__heading u-mt-0">Libraries & institutions</h3> <ul class="c-footer__list"> <li class="c-footer__item"><a class="c-footer__link" href="https://www.springernature.com/gp/librarians/tools-services" data-track="click" data-track-action="librarian service and tools" data-track-label="link">Librarian service & tools</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.springernature.com/gp/librarians/manage-your-account/librarianportal" data-track="click" data-track-action="librarian portal" data-track-label="link">Librarian portal</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/openresearch/about-open-access/information-for-institutions" data-track="click" data-track-action="open research" data-track-label="link">Open research</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.springernature.com/gp/librarians/recommend-to-your-library" data-track="click" data-track-action="Recommend to library" data-track-label="link">Recommend to library</a></li> </ul> </div> <div class="c-footer__group"> <h3 class="c-footer__heading u-mt-0">Advertising & partnerships</h3> <ul class="c-footer__list"> <li class="c-footer__item"><a class="c-footer__link" href="https://partnerships.nature.com/product/digital-advertising/" data-track="click" data-track-action="advertising" data-track-label="link">Advertising</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://partnerships.nature.com/" data-track="click" data-track-action="partnerships and services" data-track-label="link">Partnerships & Services</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://partnerships.nature.com/media-kits/" data-track="click" data-track-action="media kits" data-track-label="link">Media kits</a> </li> <li class="c-footer__item"><a class="c-footer__link" href="https://partnerships.nature.com/product/branded-content-native-advertising/" data-track-action="branded content" data-track-label="link">Branded content</a></li> </ul> </div> <div class="c-footer__group"> <h3 class="c-footer__heading u-mt-0">Professional development</h3> <ul class="c-footer__list"> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/naturecareers/" data-track="click" data-track-action="nature careers" data-track-label="link">Nature Careers</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://conferences.nature.com" data-track="click" data-track-action="nature conferences" data-track-label="link">Nature<span class="u-visually-hidden"> </span> Conferences</a></li> </ul> </div> <div class="c-footer__group"> <h3 class="c-footer__heading u-mt-0">Regional websites</h3> <ul class="c-footer__list"> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/natafrica" data-track="click" data-track-action="nature africa" data-track-label="link">Nature Africa</a></li> <li class="c-footer__item"><a class="c-footer__link" href="http://www.naturechina.com" data-track="click" data-track-action="nature china" data-track-label="link">Nature China</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/nindia" data-track="click" data-track-action="nature india" data-track-label="link">Nature India</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/natitaly" data-track="click" data-track-action="nature Italy" data-track-label="link">Nature Italy</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.natureasia.com/ja-jp" data-track="click" data-track-action="nature japan" data-track-label="link">Nature Japan</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/nmiddleeast" data-track="click" data-track-action="nature middle east" data-track-label="link">Nature Middle East</a></li> </ul> </div> </div> </div> <div class="c-footer__container"> <ul class="c-footer__links"> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/info/privacy" data-track="click" data-track-action="privacy policy" data-track-label="link">Privacy Policy</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/info/cookies" data-track="click" data-track-action="use of cookies" data-track-label="link">Use of cookies</a></li> <li class="c-footer__item"> <button class="optanon-toggle-display c-footer__link" onclick="javascript:;" data-cc-action="preferences" data-track="click" data-track-action="manage cookies" data-track-label="link">Your privacy choices/Manage cookies </button> </li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/info/legal-notice" data-track="click" data-track-action="legal notice" data-track-label="link">Legal notice</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/info/accessibility-statement" data-track="click" data-track-action="accessibility statement" data-track-label="link">Accessibility statement</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.nature.com/info/terms-and-conditions" data-track="click" data-track-action="terms and conditions" data-track-label="link">Terms & Conditions</a></li> <li class="c-footer__item"><a class="c-footer__link" href="https://www.springernature.com/ccpa" data-track="click" data-track-action="california privacy statement" data-track-label="link">Your US state privacy rights</a></li> </ul> </div> </div> <div class="c-footer__container"> <a href="https://www.springernature.com/" class="c-footer__link"> <img src="/static/images/logos/sn-logo-white-ea63208b81.svg" alt="Springer Nature" loading="lazy" width="200" height="20"/> </a> <p class="c-footer__legal" data-test="copyright">© 2025 Springer Nature Limited</p> </div> </div> <div class="u-visually-hidden" aria-hidden="true"> <?xml version="1.0" encoding="UTF-8"?><!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><defs><path id="a" d="M0 .74h56.72v55.24H0z"/></defs><symbol id="icon-access" viewBox="0 0 18 18"><path d="m14 8c.5522847 0 1 .44771525 1 1v7h2.5c.2761424 0 .5.2238576.5.5v1.5h-18v-1.5c0-.2761424.22385763-.5.5-.5h2.5v-7c0-.55228475.44771525-1 1-1s1 .44771525 1 1v6.9996556h8v-6.9996556c0-.55228475.4477153-1 1-1zm-8 0 2 1v5l-2 1zm6 0v7l-2-1v-5zm-2.42653766-7.59857636 7.03554716 4.92488299c.4162533.29137735.5174853.86502537.226108 1.28127873-.1721584.24594054-.4534847.39241464-.7536934.39241464h-14.16284822c-.50810197 0-.92-.41189803-.92-.92 0-.30020869.1464741-.58153499.39241464-.75369337l7.03554714-4.92488299c.34432015-.2410241.80260453-.2410241 1.14692468 0zm-.57346234 2.03988748-3.65526982 2.55868888h7.31053962z" fill-rule="evenodd"/></symbol><symbol id="icon-account" viewBox="0 0 18 18"><path d="m10.2379028 16.9048051c1.3083556-.2032362 2.5118471-.7235183 3.5294683-1.4798399-.8731327-2.5141501-2.0638925-3.935978-3.7673711-4.3188248v-1.27684611c1.1651924-.41183641 2-1.52307546 2-2.82929429 0-1.65685425-1.3431458-3-3-3-1.65685425 0-3 1.34314575-3 3 0 1.30621883.83480763 2.41745788 2 2.82929429v1.27684611c-1.70347856.3828468-2.89423845 1.8046747-3.76737114 4.3188248 1.01762123.7563216 2.22111275 1.2766037 3.52946833 1.4798399.40563808.0629726.81921174.0951949 1.23790281.0951949s.83226473-.0322223 1.2379028-.0951949zm4.3421782-2.1721994c1.4927655-1.4532925 2.419919-3.484675 2.419919-5.7326057 0-4.418278-3.581722-8-8-8s-8 3.581722-8 8c0 2.2479307.92715352 4.2793132 2.41991895 5.7326057.75688473-2.0164459 1.83949951-3.6071894 3.48926591-4.3218837-1.14534283-.70360829-1.90918486-1.96796271-1.90918486-3.410722 0-2.209139 1.790861-4 4-4s4 1.790861 4 4c0 1.44275929-.763842 2.70711371-1.9091849 3.410722 1.6497664.7146943 2.7323812 2.3054378 3.4892659 4.3218837zm-5.580081 3.2673943c-4.97056275 0-9-4.0294373-9-9 0-4.97056275 4.02943725-9 9-9 4.9705627 0 9 4.02943725 9 9 0 4.9705627-4.0294373 9-9 9z" fill-rule="evenodd"/></symbol><symbol id="icon-alert" viewBox="0 0 18 18"><path d="m4 10h2.5c.27614237 0 .5.2238576.5.5s-.22385763.5-.5.5h-3.08578644l-1.12132034 1.1213203c-.18753638.1875364-.29289322.4418903-.29289322.7071068v.1715729h14v-.1715729c0-.2652165-.1053568-.5195704-.2928932-.7071068l-1.7071068-1.7071067v-3.4142136c0-2.76142375-2.2385763-5-5-5-2.76142375 0-5 2.23857625-5 5zm3 4c0 1.1045695.8954305 2 2 2s2-.8954305 2-2zm-5 0c-.55228475 0-1-.4477153-1-1v-.1715729c0-.530433.21071368-1.0391408.58578644-1.4142135l1.41421356-1.4142136v-3c0-3.3137085 2.6862915-6 6-6s6 2.6862915 6 6v3l1.4142136 1.4142136c.3750727.3750727.5857864.8837805.5857864 1.4142135v.1715729c0 .5522847-.4477153 1-1 1h-4c0 1.6568542-1.3431458 3-3 3-1.65685425 0-3-1.3431458-3-3z" fill-rule="evenodd"/></symbol><symbol id="icon-arrow-broad" viewBox="0 0 16 16"><path d="m6.10307866 2.97190702v7.69043288l2.44965196-2.44676915c.38776071-.38730439 1.0088052-.39493524 1.38498697-.01919617.38609051.38563612.38643641 1.01053024-.00013864 1.39665039l-4.12239817 4.11754683c-.38616704.3857126-1.01187344.3861062-1.39846576-.0000311l-4.12258206-4.11773056c-.38618426-.38572979-.39254614-1.00476697-.01636437-1.38050605.38609047-.38563611 1.01018509-.38751562 1.4012233.00306241l2.44985644 2.4469734v-8.67638639c0-.54139983.43698413-.98042709.98493125-.98159081l7.89910522-.0043627c.5451687 0 .9871152.44142642.9871152.98595351s-.4419465.98595351-.9871152.98595351z" fill-rule="evenodd" transform="matrix(-1 0 0 -1 14 15)"/></symbol><symbol id="icon-arrow-down" viewBox="0 0 16 16"><path d="m3.28337502 11.5302405 4.03074001 4.176208c.37758093.3912076.98937525.3916069 1.367372-.0000316l4.03091977-4.1763942c.3775978-.3912252.3838182-1.0190815.0160006-1.4001736-.3775061-.39113013-.9877245-.39303641-1.3700683.003106l-2.39538585 2.4818345v-11.6147896l-.00649339-.11662112c-.055753-.49733869-.46370161-.88337888-.95867408-.88337888-.49497246 0-.90292107.38604019-.95867408.88337888l-.00649338.11662112v11.6147896l-2.39518594-2.4816273c-.37913917-.39282218-.98637524-.40056175-1.35419292-.0194697-.37750607.3911302-.37784433 1.0249269.00013556 1.4165479z" fill-rule="evenodd"/></symbol><symbol id="icon-arrow-left" viewBox="0 0 16 16"><path d="m4.46975946 3.28337502-4.17620792 4.03074001c-.39120768.37758093-.39160691.98937525.0000316 1.367372l4.1763942 4.03091977c.39122514.3775978 1.01908149.3838182 1.40017357.0160006.39113012-.3775061.3930364-.9877245-.00310603-1.3700683l-2.48183446-2.39538585h11.61478958l.1166211-.00649339c.4973387-.055753.8833789-.46370161.8833789-.95867408 0-.49497246-.3860402-.90292107-.8833789-.95867408l-.1166211-.00649338h-11.61478958l2.4816273-2.39518594c.39282216-.37913917.40056173-.98637524.01946965-1.35419292-.39113012-.37750607-1.02492687-.37784433-1.41654791.00013556z" fill-rule="evenodd"/></symbol><symbol id="icon-arrow-right" viewBox="0 0 16 16"><path d="m11.5302405 12.716625 4.176208-4.03074003c.3912076-.37758093.3916069-.98937525-.0000316-1.367372l-4.1763942-4.03091981c-.3912252-.37759778-1.0190815-.38381821-1.4001736-.01600053-.39113013.37750607-.39303641.98772445.003106 1.37006824l2.4818345 2.39538588h-11.6147896l-.11662112.00649339c-.49733869.055753-.88337888.46370161-.88337888.95867408 0 .49497246.38604019.90292107.88337888.95867408l.11662112.00649338h11.6147896l-2.4816273 2.39518592c-.39282218.3791392-.40056175.9863753-.0194697 1.3541929.3911302.3775061 1.0249269.3778444 1.4165479-.0001355z" fill-rule="evenodd"/></symbol><symbol id="icon-arrow-sub" viewBox="0 0 16 16"><path d="m7.89692134 4.97190702v7.69043288l-2.44965196-2.4467692c-.38776071-.38730434-1.0088052-.39493519-1.38498697-.0191961-.38609047.3856361-.38643643 1.0105302.00013864 1.3966504l4.12239817 4.1175468c.38616704.3857126 1.01187344.3861062 1.39846576-.0000311l4.12258202-4.1177306c.3861843-.3857298.3925462-1.0047669.0163644-1.380506-.3860905-.38563612-1.0101851-.38751563-1.4012233.0030624l-2.44985643 2.4469734v-8.67638639c0-.54139983-.43698413-.98042709-.98493125-.98159081l-7.89910525-.0043627c-.54516866 0-.98711517.44142642-.98711517.98595351s.44194651.98595351.98711517.98595351z" fill-rule="evenodd"/></symbol><symbol id="icon-arrow-up" viewBox="0 0 16 16"><path d="m12.716625 4.46975946-4.03074003-4.17620792c-.37758093-.39120768-.98937525-.39160691-1.367372.0000316l-4.03091981 4.1763942c-.37759778.39122514-.38381821 1.01908149-.01600053 1.40017357.37750607.39113012.98772445.3930364 1.37006824-.00310603l2.39538588-2.48183446v11.61478958l.00649339.1166211c.055753.4973387.46370161.8833789.95867408.8833789.49497246 0 .90292107-.3860402.95867408-.8833789l.00649338-.1166211v-11.61478958l2.39518592 2.4816273c.3791392.39282216.9863753.40056173 1.3541929.01946965.3775061-.39113012.3778444-1.02492687-.0001355-1.41654791z" fill-rule="evenodd"/></symbol><symbol id="icon-article" viewBox="0 0 18 18"><path d="m13 15v-12.9906311c0-.0073595-.0019884-.0093689.0014977-.0093689l-11.00158888.00087166v13.00506804c0 .5482678.44615281.9940603.99415146.9940603h10.27350412c-.1701701-.2941734-.2675644-.6357129-.2675644-1zm-12 .0059397v-13.00506804c0-.5562408.44704472-1.00087166.99850233-1.00087166h11.00299537c.5510129 0 .9985023.45190985.9985023 1.0093689v2.9906311h3v9.9914698c0 1.1065798-.8927712 2.0085302-1.9940603 2.0085302h-12.01187942c-1.09954652 0-1.99406028-.8927712-1.99406028-1.9940603zm13-9.0059397v9c0 .5522847.4477153 1 1 1s1-.4477153 1-1v-9zm-10-2h7v4h-7zm1 1v2h5v-2zm-1 4h7v1h-7zm0 2h7v1h-7zm0 2h7v1h-7z" fill-rule="evenodd"/></symbol><symbol id="icon-audio" viewBox="0 0 18 18"><path d="m13.0957477 13.5588459c-.195279.1937043-.5119137.193729-.7072234.0000551-.1953098-.193674-.1953346-.5077061-.0000556-.7014104 1.0251004-1.0168342 1.6108711-2.3905226 1.6108711-3.85745208 0-1.46604976-.5850634-2.83898246-1.6090736-3.85566829-.1951894-.19379323-.1950192-.50782531.0003802-.70141028.1953993-.19358497.512034-.19341614.7072234.00037709 1.2094886 1.20083761 1.901635 2.8250555 1.901635 4.55670148 0 1.73268608-.6929822 3.35779608-1.9037571 4.55880738zm2.1233994 2.1025159c-.195234.193749-.5118687.1938462-.7072235.0002171-.1953548-.1936292-.1954528-.5076613-.0002189-.7014104 1.5832215-1.5711805 2.4881302-3.6939808 2.4881302-5.96012998 0-2.26581266-.9046382-4.3883241-2.487443-5.95944795-.1952117-.19377107-.1950777-.50780316.0002993-.70141031s.5120117-.19347426.7072234.00029682c1.7683321 1.75528196 2.7800854 4.12911258 2.7800854 6.66056144 0 2.53182498-1.0120556 4.90597838-2.7808529 6.66132328zm-14.21898205-3.6854911c-.5523759 0-1.00016505-.4441085-1.00016505-.991944v-3.96777631c0-.54783558.44778915-.99194407 1.00016505-.99194407h2.0003301l5.41965617-3.8393633c.44948677-.31842296 1.07413994-.21516983 1.39520191.23062232.12116339.16823446.18629727.36981184.18629727.57655577v12.01603479c0 .5478356-.44778914.9919441-1.00016505.9919441-.20845738 0-.41170538-.0645985-.58133413-.184766l-5.41965617-3.8393633zm0-.991944h2.32084805l5.68047235 4.0241292v-12.01603479l-5.68047235 4.02412928h-2.32084805z" fill-rule="evenodd"/></symbol><symbol id="icon-block" viewBox="0 0 24 24"><path d="m0 0h24v24h-24z" fill-rule="evenodd"/></symbol><symbol id="icon-book" viewBox="0 0 18 18"><path d="m4 13v-11h1v11h11v-11h-13c-.55228475 0-1 .44771525-1 1v10.2675644c.29417337-.1701701.63571286-.2675644 1-.2675644zm12 1h-13c-.55228475 0-1 .4477153-1 1s.44771525 1 1 1h13zm0 3h-13c-1.1045695 0-2-.8954305-2-2v-12c0-1.1045695.8954305-2 2-2h13c.5522847 0 1 .44771525 1 1v14c0 .5522847-.4477153 1-1 1zm-8.5-13h6c.2761424 0 .5.22385763.5.5s-.2238576.5-.5.5h-6c-.27614237 0-.5-.22385763-.5-.5s.22385763-.5.5-.5zm1 2h4c.2761424 0 .5.22385763.5.5s-.2238576.5-.5.5h-4c-.27614237 0-.5-.22385763-.5-.5s.22385763-.5.5-.5z" fill-rule="evenodd"/></symbol><symbol id="icon-broad" viewBox="0 0 24 24"><path d="m9.18274226 7.81v7.7999954l2.48162734-2.4816273c.3928221-.3928221 1.0219731-.4005617 1.4030652-.0194696.3911301.3911301.3914806 1.0249268-.0001404 1.4165479l-4.17620796 4.1762079c-.39120769.3912077-1.02508144.3916069-1.41671995-.0000316l-4.1763942-4.1763942c-.39122514-.3912251-.39767006-1.0190815-.01657798-1.4001736.39113012-.3911301 1.02337106-.3930364 1.41951349.0031061l2.48183446 2.4818344v-8.7999954c0-.54911294.4426881-.99439484.99778758-.99557515l8.00221246-.00442485c.5522847 0 1 .44771525 1 1s-.4477153 1-1 1z" fill-rule="evenodd" transform="matrix(-1 0 0 -1 20.182742 24.805206)"/></symbol><symbol id="icon-calendar" viewBox="0 0 18 18"><path d="m12.5 0c.2761424 0 .5.21505737.5.49047852v.50952148h2c1.1072288 0 2 .89451376 2 2v12c0 1.1072288-.8945138 2-2 2h-12c-1.1072288 0-2-.8945138-2-2v-12c0-1.1072288.89451376-2 2-2h1v1h-1c-.55393837 0-1 .44579254-1 1v3h14v-3c0-.55393837-.4457925-1-1-1h-2v1.50952148c0 .27088381-.2319336.49047852-.5.49047852-.2761424 0-.5-.21505737-.5-.49047852v-3.01904296c0-.27088381.2319336-.49047852.5-.49047852zm3.5 7h-14v8c0 .5539384.44579254 1 1 1h12c.5539384 0 1-.4457925 1-1zm-11 6v1h-1v-1zm3 0v1h-1v-1zm3 0v1h-1v-1zm-6-2v1h-1v-1zm3 0v1h-1v-1zm6 0v1h-1v-1zm-3 0v1h-1v-1zm-3-2v1h-1v-1zm6 0v1h-1v-1zm-3 0v1h-1v-1zm-5.5-9c.27614237 0 .5.21505737.5.49047852v.50952148h5v1h-5v1.50952148c0 .27088381-.23193359.49047852-.5.49047852-.27614237 0-.5-.21505737-.5-.49047852v-3.01904296c0-.27088381.23193359-.49047852.5-.49047852z" fill-rule="evenodd"/></symbol><symbol id="icon-cart" viewBox="0 0 18 18"><path d="m5 14c1.1045695 0 2 .8954305 2 2s-.8954305 2-2 2-2-.8954305-2-2 .8954305-2 2-2zm10 0c1.1045695 0 2 .8954305 2 2s-.8954305 2-2 2-2-.8954305-2-2 .8954305-2 2-2zm-10 1c-.55228475 0-1 .4477153-1 1s.44771525 1 1 1 1-.4477153 1-1-.44771525-1-1-1zm10 0c-.5522847 0-1 .4477153-1 1s.4477153 1 1 1 1-.4477153 1-1-.4477153-1-1-1zm-12.82032249-15c.47691417 0 .88746157.33678127.98070211.80449199l.23823144 1.19501025 13.36277974.00045554c.5522847.00001882.9999659.44774934.9999659 1.00004222 0 .07084994-.0075361.14150708-.022474.2107727l-1.2908094 5.98534344c-.1007861.46742419-.5432548.80388386-1.0571651.80388386h-10.24805106c-.59173366 0-1.07142857.4477153-1.07142857 1 0 .5128358.41361449.9355072.94647737.9932723l.1249512.0067277h10.35933776c.2749512 0 .4979349.2228539.4979349.4978051 0 .2749417-.2227336.4978951-.4976753.4980063l-10.35959736.0041886c-1.18346732 0-2.14285714-.8954305-2.14285714-2 0-.6625717.34520317-1.24989198.87690425-1.61383592l-1.63768102-8.19004794c-.01312273-.06561364-.01950005-.131011-.0196107-.19547395l-1.71961253-.00064219c-.27614237 0-.5-.22385762-.5-.5 0-.27614237.22385763-.5.5-.5zm14.53193359 2.99950224h-13.11300004l1.20580469 6.02530174c.11024034-.0163252.22327998-.02480398.33844139-.02480398h10.27064786z"/></symbol><symbol id="icon-chevron-less" viewBox="0 0 10 10"><path d="m5.58578644 4-3.29289322-3.29289322c-.39052429-.39052429-.39052429-1.02368927 0-1.41421356s1.02368927-.39052429 1.41421356 0l4 4c.39052429.39052429.39052429 1.02368927 0 1.41421356l-4 4c-.39052429.39052429-1.02368927.39052429-1.41421356 0s-.39052429-1.02368927 0-1.41421356z" fill-rule="evenodd" transform="matrix(0 -1 -1 0 9 9)"/></symbol><symbol id="icon-chevron-more" viewBox="0 0 10 10"><path d="m5.58578644 6-3.29289322-3.29289322c-.39052429-.39052429-.39052429-1.02368927 0-1.41421356s1.02368927-.39052429 1.41421356 0l4 4c.39052429.39052429.39052429 1.02368927 0 1.41421356l-4 4.00000002c-.39052429.3905243-1.02368927.3905243-1.41421356 0s-.39052429-1.02368929 0-1.41421358z" fill-rule="evenodd" transform="matrix(0 1 -1 0 11 1)"/></symbol><symbol id="icon-chevron-right" viewBox="0 0 10 10"><path d="m5.96738168 4.70639573 2.39518594-2.41447274c.37913917-.38219212.98637524-.38972225 1.35419292-.01894278.37750606.38054586.37784436.99719163-.00013556 1.37821513l-4.03074001 4.06319683c-.37758093.38062133-.98937525.38100976-1.367372-.00003075l-4.03091981-4.06337806c-.37759778-.38063832-.38381821-.99150444-.01600053-1.3622839.37750607-.38054587.98772445-.38240057 1.37006824.00302197l2.39538588 2.4146743.96295325.98624457z" fill-rule="evenodd" transform="matrix(0 -1 1 0 0 10)"/></symbol><symbol id="icon-circle-fill" viewBox="0 0 16 16"><path d="m8 14c-3.3137085 0-6-2.6862915-6-6s2.6862915-6 6-6 6 2.6862915 6 6-2.6862915 6-6 6z" fill-rule="evenodd"/></symbol><symbol id="icon-circle" viewBox="0 0 16 16"><path d="m8 12c2.209139 0 4-1.790861 4-4s-1.790861-4-4-4-4 1.790861-4 4 1.790861 4 4 4zm0 2c-3.3137085 0-6-2.6862915-6-6s2.6862915-6 6-6 6 2.6862915 6 6-2.6862915 6-6 6z" fill-rule="evenodd"/></symbol><symbol id="icon-citation" viewBox="0 0 18 18"><path d="m8.63593473 5.99995183c2.20913897 0 3.99999997 1.79084375 3.99999997 3.99996146 0 1.40730761-.7267788 2.64486871-1.8254829 3.35783281 1.6240224.6764218 2.8754442 2.0093871 3.4610603 3.6412466l-1.0763845.000006c-.5310008-1.2078237-1.5108121-2.1940153-2.7691712-2.7181346l-.79002167-.329052v-1.023992l.63016577-.4089232c.8482885-.5504661 1.3698342-1.4895187 1.3698342-2.51898361 0-1.65683828-1.3431457-2.99996146-2.99999997-2.99996146-1.65685425 0-3 1.34312318-3 2.99996146 0 1.02946491.52154569 1.96851751 1.36983419 2.51898361l.63016581.4089232v1.023992l-.79002171.329052c-1.25835905.5241193-2.23817037 1.5103109-2.76917113 2.7181346l-1.07638453-.000006c.58561612-1.6318595 1.8370379-2.9648248 3.46106024-3.6412466-1.09870405-.7129641-1.82548287-1.9505252-1.82548287-3.35783281 0-2.20911771 1.790861-3.99996146 4-3.99996146zm7.36897597-4.99995183c1.1018574 0 1.9950893.89353404 1.9950893 2.00274083v5.994422c0 1.10608317-.8926228 2.00274087-1.9950893 2.00274087l-3.0049107-.0009037v-1l3.0049107.00091329c.5490631 0 .9950893-.44783123.9950893-1.00275046v-5.994422c0-.55646537-.4450595-1.00275046-.9950893-1.00275046h-14.00982141c-.54906309 0-.99508929.44783123-.99508929 1.00275046v5.9971821c0 .66666024.33333333.99999036 1 .99999036l2-.00091329v1l-2 .0009037c-1 0-2-.99999041-2-1.99998077v-5.9971821c0-1.10608322.8926228-2.00274083 1.99508929-2.00274083zm-8.5049107 2.9999711c.27614237 0 .5.22385547.5.5 0 .2761349-.22385763.5-.5.5h-4c-.27614237 0-.5-.2238651-.5-.5 0-.27614453.22385763-.5.5-.5zm3 0c.2761424 0 .5.22385547.5.5 0 .2761349-.2238576.5-.5.5h-1c-.27614237 0-.5-.2238651-.5-.5 0-.27614453.22385763-.5.5-.5zm4 0c.2761424 0 .5.22385547.5.5 0 .2761349-.2238576.5-.5.5h-2c-.2761424 0-.5-.2238651-.5-.5 0-.27614453.2238576-.5.5-.5z" fill-rule="evenodd"/></symbol><symbol id="icon-close" viewBox="0 0 16 16"><path d="m2.29679575 12.2772478c-.39658757.3965876-.39438847 1.0328109-.00062148 1.4265779.39651227.3965123 1.03246768.3934888 1.42657791-.0006214l4.27724782-4.27724787 4.2772478 4.27724787c.3965876.3965875 1.0328109.3943884 1.4265779.0006214.3965123-.3965122.3934888-1.0324677-.0006214-1.4265779l-4.27724787-4.2772478 4.27724787-4.27724782c.3965875-.39658757.3943884-1.03281091.0006214-1.42657791-.3965122-.39651226-1.0324677-.39348875-1.4265779.00062148l-4.2772478 4.27724782-4.27724782-4.27724782c-.39658757-.39658757-1.03281091-.39438847-1.42657791-.00062148-.39651226.39651227-.39348875 1.03246768.00062148 1.42657791l4.27724782 4.27724782z" fill-rule="evenodd"/></symbol><symbol id="icon-collections" viewBox="0 0 18 18"><path d="m15 4c1.1045695 0 2 .8954305 2 2v9c0 1.1045695-.8954305 2-2 2h-8c-1.1045695 0-2-.8954305-2-2h1c0 .5128358.38604019.9355072.88337887.9932723l.11662113.0067277h8c.5128358 0 .9355072-.3860402.9932723-.8833789l.0067277-.1166211v-9c0-.51283584-.3860402-.93550716-.8833789-.99327227l-.1166211-.00672773h-1v-1zm-4-3c1.1045695 0 2 .8954305 2 2v9c0 1.1045695-.8954305 2-2 2h-8c-1.1045695 0-2-.8954305-2-2v-9c0-1.1045695.8954305-2 2-2zm0 1h-8c-.51283584 0-.93550716.38604019-.99327227.88337887l-.00672773.11662113v9c0 .5128358.38604019.9355072.88337887.9932723l.11662113.0067277h8c.5128358 0 .9355072-.3860402.9932723-.8833789l.0067277-.1166211v-9c0-.51283584-.3860402-.93550716-.8833789-.99327227zm-1.5 7c.27614237 0 .5.22385763.5.5s-.22385763.5-.5.5h-5c-.27614237 0-.5-.22385763-.5-.5s.22385763-.5.5-.5zm0-2c.27614237 0 .5.22385763.5.5s-.22385763.5-.5.5h-5c-.27614237 0-.5-.22385763-.5-.5s.22385763-.5.5-.5zm0-2c.27614237 0 .5.22385763.5.5s-.22385763.5-.5.5h-5c-.27614237 0-.5-.22385763-.5-.5s.22385763-.5.5-.5z" fill-rule="evenodd"/></symbol><symbol id="icon-compare" viewBox="0 0 18 18"><path d="m12 3c3.3137085 0 6 2.6862915 6 6s-2.6862915 6-6 6c-1.0928452 0-2.11744941-.2921742-2.99996061-.8026704-.88181407.5102749-1.90678042.8026704-3.00003939.8026704-3.3137085 0-6-2.6862915-6-6s2.6862915-6 6-6c1.09325897 0 2.11822532.29239547 3.00096303.80325037.88158756-.51107621 1.90619177-.80325037 2.99903697-.80325037zm-6 1c-2.76142375 0-5 2.23857625-5 5 0 2.7614237 2.23857625 5 5 5 .74397391 0 1.44999672-.162488 2.08451611-.4539116-1.27652344-1.1000812-2.08451611-2.7287264-2.08451611-4.5460884s.80799267-3.44600721 2.08434391-4.5463015c-.63434719-.29121054-1.34037-.4536985-2.08434391-.4536985zm6 0c-.7439739 0-1.4499967.16248796-2.08451611.45391156 1.27652341 1.10008123 2.08451611 2.72872644 2.08451611 4.54608844s-.8079927 3.4460072-2.08434391 4.5463015c.63434721.2912105 1.34037001.4536985 2.08434391.4536985 2.7614237 0 5-2.2385763 5-5 0-2.76142375-2.2385763-5-5-5zm-1.4162763 7.0005324h-3.16744736c.15614659.3572676.35283837.6927622.58425872 1.0006671h1.99892988c.23142036-.3079049.42811216-.6433995.58425876-1.0006671zm.4162763-2.0005324h-4c0 .34288501.0345146.67770871.10025909 1.0011864h3.79948181c.0657445-.32347769.1002591-.65830139.1002591-1.0011864zm-.4158423-1.99953894h-3.16831543c-.13859957.31730812-.24521946.651783-.31578599.99935097h3.79988742c-.0705665-.34756797-.1771864-.68204285-.315786-.99935097zm-1.58295822-1.999926-.08316107.06199199c-.34550042.27081213-.65446126.58611297-.91825862.93727862h2.00044041c-.28418626-.37830727-.6207872-.71499149-.99902072-.99927061z" fill-rule="evenodd"/></symbol><symbol id="icon-download-file" viewBox="0 0 18 18"><path d="m10.0046024 0c.5497429 0 1.3179837.32258606 1.707238.71184039l4.5763192 4.57631922c.3931386.39313859.7118404 1.16760135.7118404 1.71431368v8.98899651c0 1.1092806-.8945138 2.0085302-1.9940603 2.0085302h-12.01187942c-1.10128908 0-1.99406028-.8926228-1.99406028-1.9950893v-14.00982141c0-1.10185739.88743329-1.99508929 1.99961498-1.99508929zm0 1h-7.00498742c-.55709576 0-.99961498.44271433-.99961498.99508929v14.00982141c0 .5500396.44491393.9950893.99406028.9950893h12.01187942c.5463747 0 .9940603-.4506622.9940603-1.0085302v-8.98899651c0-.28393444-.2150684-.80332809-.4189472-1.0072069l-4.5763192-4.57631922c-.2038461-.20384606-.718603-.41894717-1.0001312-.41894717zm-1.5046024 4c.27614237 0 .5.21637201.5.49209595v6.14827645l1.7462789-1.77990922c.1933927-.1971171.5125222-.19455839.7001689-.0069117.1932998.19329992.1910058.50899492-.0027774.70277812l-2.59089271 2.5908927c-.19483374.1948337-.51177825.1937771-.70556873-.0000133l-2.59099079-2.5909908c-.19484111-.1948411-.19043735-.5151448-.00279066-.70279146.19329987-.19329987.50465175-.19237083.70018565.00692852l1.74638684 1.78001764v-6.14827695c0-.27177709.23193359-.49209595.5-.49209595z" fill-rule="evenodd"/></symbol><symbol id="icon-download" viewBox="0 0 16 16"><path d="m12.9975267 12.999368c.5467123 0 1.0024733.4478567 1.0024733 1.000316 0 .5563109-.4488226 1.000316-1.0024733 1.000316h-9.99505341c-.54671233 0-1.00247329-.4478567-1.00247329-1.000316 0-.5563109.44882258-1.000316 1.00247329-1.000316zm-4.9975267-11.999368c.55228475 0 1 .44497754 1 .99589209v6.80214418l2.4816273-2.48241149c.3928222-.39294628 1.0219732-.4006883 1.4030652-.01947579.3911302.39125371.3914806 1.02525073-.0001404 1.41699553l-4.17620792 4.17752758c-.39120769.3913313-1.02508144.3917306-1.41671995-.0000316l-4.17639421-4.17771394c-.39122513-.39134876-.39767006-1.01940351-.01657797-1.40061601.39113012-.39125372 1.02337105-.3931606 1.41951349.00310701l2.48183446 2.48261871v-6.80214418c0-.55001601.44386482-.99589209 1-.99589209z" fill-rule="evenodd"/></symbol><symbol id="icon-editors" viewBox="0 0 18 18"><path d="m8.72592184 2.54588137c-.48811714-.34391207-1.08343326-.54588137-1.72592184-.54588137-1.65685425 0-3 1.34314575-3 3 0 1.02947485.5215457 1.96853646 1.3698342 2.51900785l.6301658.40892721v1.02400182l-.79002171.32905522c-1.93395773.8055207-3.20997829 2.7024791-3.20997829 4.8180274v.9009805h-1v-.9009805c0-2.5479714 1.54557359-4.79153984 3.82548288-5.7411543-1.09870406-.71297106-1.82548288-1.95054399-1.82548288-3.3578652 0-2.209139 1.790861-4 4-4 1.09079823 0 2.07961816.43662103 2.80122451 1.1446278-.37707584.09278571-.7373238.22835063-1.07530267.40125357zm-2.72592184 14.45411863h-1v-.9009805c0-2.5479714 1.54557359-4.7915398 3.82548288-5.7411543-1.09870406-.71297106-1.82548288-1.95054399-1.82548288-3.3578652 0-2.209139 1.790861-4 4-4s4 1.790861 4 4c0 1.40732121-.7267788 2.64489414-1.8254829 3.3578652 2.2799093.9496145 3.8254829 3.1931829 3.8254829 5.7411543v.9009805h-1v-.9009805c0-2.1155483-1.2760206-4.0125067-3.2099783-4.8180274l-.7900217-.3290552v-1.02400184l.6301658-.40892721c.8482885-.55047139 1.3698342-1.489533 1.3698342-2.51900785 0-1.65685425-1.3431458-3-3-3-1.65685425 0-3 1.34314575-3 3 0 1.02947485.5215457 1.96853646 1.3698342 2.51900785l.6301658.40892721v1.02400184l-.79002171.3290552c-1.93395773.8055207-3.20997829 2.7024791-3.20997829 4.8180274z" fill-rule="evenodd"/></symbol><symbol id="icon-email" viewBox="0 0 18 18"><path d="m16.0049107 2c1.1018574 0 1.9950893.89706013 1.9950893 2.00585866v9.98828264c0 1.1078052-.8926228 2.0058587-1.9950893 2.0058587h-14.00982141c-1.10185739 0-1.99508929-.8970601-1.99508929-2.0058587v-9.98828264c0-1.10780515.8926228-2.00585866 1.99508929-2.00585866zm0 1h-14.00982141c-.54871518 0-.99508929.44887827-.99508929 1.00585866v9.98828264c0 .5572961.44630695 1.0058587.99508929 1.0058587h14.00982141c.5487152 0 .9950893-.4488783.9950893-1.0058587v-9.98828264c0-.55729607-.446307-1.00585866-.9950893-1.00585866zm-.0049107 2.55749512v1.44250488l-7 4-7-4v-1.44250488l7 4z" fill-rule="evenodd"/></symbol><symbol id="icon-error" viewBox="0 0 18 18"><path d="m9 0c4.9705627 0 9 4.02943725 9 9 0 4.9705627-4.0294373 9-9 9-4.97056275 0-9-4.0294373-9-9 0-4.97056275 4.02943725-9 9-9zm2.8630343 4.71100931-2.8630343 2.86303426-2.86303426-2.86303426c-.39658757-.39658757-1.03281091-.39438847-1.4265779-.00062147-.39651227.39651226-.39348876 1.03246767.00062147 1.4265779l2.86303426 2.86303426-2.86303426 2.8630343c-.39658757.3965875-.39438847 1.0328109-.00062147 1.4265779.39651226.3965122 1.03246767.3934887 1.4265779-.0006215l2.86303426-2.8630343 2.8630343 2.8630343c.3965875.3965876 1.0328109.3943885 1.4265779.0006215.3965122-.3965123.3934887-1.0324677-.0006215-1.4265779l-2.8630343-2.8630343 2.8630343-2.86303426c.3965876-.39658757.3943885-1.03281091.0006215-1.4265779-.3965123-.39651227-1.0324677-.39348876-1.4265779.00062147z" fill-rule="evenodd"/></symbol><symbol id="icon-ethics" viewBox="0 0 18 18"><path d="m6.76384967 1.41421356.83301651-.8330165c.77492941-.77492941 2.03133823-.77492941 2.80626762 0l.8330165.8330165c.3750728.37507276.8837806.58578644 1.4142136.58578644h1.3496361c1.1045695 0 2 .8954305 2 2v1.34963611c0 .53043298.2107137 1.03914081.5857864 1.41421356l.8330165.83301651c.7749295.77492941.7749295 2.03133823 0 2.80626762l-.8330165.8330165c-.3750727.3750728-.5857864.8837806-.5857864 1.4142136v1.3496361c0 1.1045695-.8954305 2-2 2h-1.3496361c-.530433 0-1.0391408.2107137-1.4142136.5857864l-.8330165.8330165c-.77492939.7749295-2.03133821.7749295-2.80626762 0l-.83301651-.8330165c-.37507275-.3750727-.88378058-.5857864-1.41421356-.5857864h-1.34963611c-1.1045695 0-2-.8954305-2-2v-1.3496361c0-.530433-.21071368-1.0391408-.58578644-1.4142136l-.8330165-.8330165c-.77492941-.77492939-.77492941-2.03133821 0-2.80626762l.8330165-.83301651c.37507276-.37507275.58578644-.88378058.58578644-1.41421356v-1.34963611c0-1.1045695.8954305-2 2-2h1.34963611c.53043298 0 1.03914081-.21071368 1.41421356-.58578644zm-1.41421356 1.58578644h-1.34963611c-.55228475 0-1 .44771525-1 1v1.34963611c0 .79564947-.31607052 1.55871121-.87867966 2.12132034l-.8330165.83301651c-.38440512.38440512-.38440512 1.00764896 0 1.39205408l.8330165.83301646c.56260914.5626092.87867966 1.3256709.87867966 2.1213204v1.3496361c0 .5522847.44771525 1 1 1h1.34963611c.79564947 0 1.55871121.3160705 2.12132034.8786797l.83301651.8330165c.38440512.3844051 1.00764896.3844051 1.39205408 0l.83301646-.8330165c.5626092-.5626092 1.3256709-.8786797 2.1213204-.8786797h1.3496361c.5522847 0 1-.4477153 1-1v-1.3496361c0-.7956495.3160705-1.5587112.8786797-2.1213204l.8330165-.83301646c.3844051-.38440512.3844051-1.00764896 0-1.39205408l-.8330165-.83301651c-.5626092-.56260913-.8786797-1.32567087-.8786797-2.12132034v-1.34963611c0-.55228475-.4477153-1-1-1h-1.3496361c-.7956495 0-1.5587112-.31607052-2.1213204-.87867966l-.83301646-.8330165c-.38440512-.38440512-1.00764896-.38440512-1.39205408 0l-.83301651.8330165c-.56260913.56260914-1.32567087.87867966-2.12132034.87867966zm3.58698944 11.4960218c-.02081224.002155-.04199226.0030286-.06345763.002542-.98766446-.0223875-1.93408568-.3063547-2.75885125-.8155622-.23496767-.1450683-.30784554-.4531483-.16277726-.688116.14506827-.2349677.45314827-.3078455.68811595-.1627773.67447084.4164161 1.44758575.6483839 2.25617384.6667123.01759529.0003988.03495764.0017019.05204365.0038639.01713363-.0017748.03452416-.0026845.05212715-.0026845 2.4852814 0 4.5-2.0147186 4.5-4.5 0-1.04888973-.3593547-2.04134635-1.0074477-2.83787157-.1742817-.21419731-.1419238-.5291218.0722736-.70340353.2141973-.17428173.5291218-.14192375.7034035.07227357.7919032.97327203 1.2317706 2.18808682 1.2317706 3.46900153 0 3.0375661-2.4624339 5.5-5.5 5.5-.02146768 0-.04261937-.0013529-.06337445-.0039782zm1.57975095-10.78419583c.2654788.07599731.419084.35281842.3430867.61829728-.0759973.26547885-.3528185.419084-.6182973.3430867-.37560116-.10752146-.76586237-.16587951-1.15568824-.17249193-2.5587807-.00064534-4.58547766 2.00216524-4.58547766 4.49928198 0 .62691557.12797645 1.23496.37274865 1.7964426.11035133.2531347-.0053975.5477984-.25853224.6581497-.25313473.1103514-.54779841-.0053975-.65814974-.2585322-.29947131-.6869568-.45606667-1.43097603-.45606667-2.1960601 0-3.05211432 2.47714695-5.50006595 5.59399617-5.49921198.48576182.00815502.96289603.0795037 1.42238033.21103795zm-1.9766658 6.41091303 2.69835-2.94655317c.1788432-.21040373.4943901-.23598862.7047939-.05714545.2104037.17884318.2359886.49439014.0571454.70479387l-3.01637681 3.34277395c-.18039088.1999106-.48669547.2210637-.69285412.0478478l-1.93095347-1.62240047c-.21213845-.17678204-.24080048-.49206439-.06401844-.70420284.17678204-.21213844.49206439-.24080048.70420284-.06401844z" fill-rule="evenodd"/></symbol><symbol id="icon-expand"><path d="M7.498 11.918a.997.997 0 0 0-.003-1.411.995.995 0 0 0-1.412-.003l-4.102 4.102v-3.51A1 1 0 0 0 .98 10.09.992.992 0 0 0 0 11.092V17c0 .554.448 1.002 1.002 1.002h5.907c.554 0 1.002-.45 1.002-1.003 0-.539-.45-.978-1.006-.978h-3.51zm3.005-5.835a.997.997 0 0 0 .003 1.412.995.995 0 0 0 1.411.003l4.103-4.103v3.51a1 1 0 0 0 1.001 1.006A.992.992 0 0 0 18 6.91V1.002A1 1 0 0 0 17 0h-5.907a1.003 1.003 0 0 0-1.002 1.003c0 .539.45.978 1.006.978h3.51z" fill-rule="evenodd"/></symbol><symbol id="icon-explore" viewBox="0 0 18 18"><path d="m9 17c4.418278 0 8-3.581722 8-8s-3.581722-8-8-8-8 3.581722-8 8 3.581722 8 8 8zm0 1c-4.97056275 0-9-4.0294373-9-9 0-4.97056275 4.02943725-9 9-9 4.9705627 0 9 4.02943725 9 9 0 4.9705627-4.0294373 9-9 9zm0-2.5c-.27614237 0-.5-.2238576-.5-.5s.22385763-.5.5-.5c2.969509 0 5.400504-2.3575119 5.497023-5.31714844.0090007-.27599565.2400359-.49243782.5160315-.48343711.2759957.0090007.4924378.2400359.4834371.51603155-.114093 3.4985237-2.9869632 6.284554-6.4964916 6.284554zm-.29090657-12.99359748c.27587424-.01216621.50937715.20161139.52154336.47748563.01216621.27587423-.20161139.50937715-.47748563.52154336-2.93195733.12930094-5.25315116 2.54886451-5.25315116 5.49456849 0 .27614237-.22385763.5-.5.5s-.5-.22385763-.5-.5c0-3.48142406 2.74307146-6.34074398 6.20909343-6.49359748zm1.13784138 8.04763908-1.2004882-1.20048821c-.19526215-.19526215-.19526215-.51184463 0-.70710678s.51184463-.19526215.70710678 0l1.20048821 1.2004882 1.6006509-4.00162734-4.50670359 1.80268144-1.80268144 4.50670359zm4.10281269-6.50378907-2.6692597 6.67314927c-.1016411.2541026-.3029834.4554449-.557086.557086l-6.67314927 2.6692597 2.66925969-6.67314926c.10164107-.25410266.30298336-.45544495.55708602-.55708602z" fill-rule="evenodd"/></symbol><symbol id="icon-filter" viewBox="0 0 16 16"><path d="m14.9738641 0c.5667192 0 1.0261359.4477136 1.0261359 1 0 .24221858-.0902161.47620768-.2538899.65849851l-5.6938314 6.34147206v5.49997973c0 .3147562-.1520673.6111434-.4104543.7999971l-2.05227171 1.4999945c-.45337535.3313696-1.09655869.2418269-1.4365902-.1999993-.13321514-.1730955-.20522717-.3836284-.20522717-.5999978v-6.99997423l-5.69383133-6.34147206c-.3731872-.41563511-.32996891-1.0473954.09653074-1.41107611.18705584-.15950448.42716133-.2474224.67571519-.2474224zm-5.9218641 8.5h-2.105v6.491l.01238459.0070843.02053271.0015705.01955278-.0070558 2.0532976-1.4990996zm-8.02585008-7.5-.01564945.00240169 5.83249953 6.49759831h2.313l5.836-6.499z"/></symbol><symbol id="icon-home" viewBox="0 0 18 18"><path d="m9 5-6 6v5h4v-4h4v4h4v-5zm7 6.5857864v4.4142136c0 .5522847-.4477153 1-1 1h-5v-4h-2v4h-5c-.55228475 0-1-.4477153-1-1v-4.4142136c-.25592232 0-.51184464-.097631-.70710678-.2928932l-.58578644-.5857864c-.39052429-.3905243-.39052429-1.02368929 0-1.41421358l8.29289322-8.29289322 8.2928932 8.29289322c.3905243.39052429.3905243 1.02368928 0 1.41421358l-.5857864.5857864c-.1952622.1952622-.4511845.2928932-.7071068.2928932zm-7-9.17157284-7.58578644 7.58578644.58578644.5857864 7-6.99999996 7 6.99999996.5857864-.5857864z" fill-rule="evenodd"/></symbol><symbol id="icon-image" viewBox="0 0 18 18"><path d="m10.0046024 0c.5497429 0 1.3179837.32258606 1.707238.71184039l4.5763192 4.57631922c.3931386.39313859.7118404 1.16760135.7118404 1.71431368v8.98899651c0 1.1092806-.8945138 2.0085302-1.9940603 2.0085302h-12.01187942c-1.10128908 0-1.99406028-.8926228-1.99406028-1.9950893v-14.00982141c0-1.10185739.88743329-1.99508929 1.99961498-1.99508929zm-3.49645283 10.1752453-3.89407257 6.7495552c.11705545.048464.24538859.0751995.37998328.0751995h10.60290092l-2.4329715-4.2154691-1.57494129 2.7288098zm8.49779013 6.8247547c.5463747 0 .9940603-.4506622.9940603-1.0085302v-8.98899651c0-.28393444-.2150684-.80332809-.4189472-1.0072069l-4.5763192-4.57631922c-.2038461-.20384606-.718603-.41894717-1.0001312-.41894717h-7.00498742c-.55709576 0-.99961498.44271433-.99961498.99508929v13.98991071l4.50814957-7.81026689 3.08089884 5.33809539 1.57494129-2.7288097 3.5875735 6.2159812zm-3.0059397-11c1.1045695 0 2 .8954305 2 2s-.8954305 2-2 2-2-.8954305-2-2 .8954305-2 2-2zm0 1c-.5522847 0-1 .44771525-1 1s.4477153 1 1 1 1-.44771525 1-1-.4477153-1-1-1z" fill-rule="evenodd"/></symbol><symbol id="icon-info" viewBox="0 0 18 18"><path d="m9 0c4.9705627 0 9 4.02943725 9 9 0 4.9705627-4.0294373 9-9 9-4.97056275 0-9-4.0294373-9-9 0-4.97056275 4.02943725-9 9-9zm0 7h-1.5l-.11662113.00672773c-.49733868.05776511-.88337887.48043643-.88337887.99327227 0 .47338693.32893365.86994729.77070917.97358929l.1126697.01968298.11662113.00672773h.5v3h-.5l-.11662113.0067277c-.42082504.0488782-.76196299.3590206-.85696816.7639815l-.01968298.1126697-.00672773.1166211.00672773.1166211c.04887817.4208251.35902055.761963.76398144.8569682l.1126697.019683.11662113.0067277h3l.1166211-.0067277c.4973387-.0577651.8833789-.4804365.8833789-.9932723 0-.4733869-.3289337-.8699473-.7707092-.9735893l-.1126697-.019683-.1166211-.0067277h-.5v-4l-.00672773-.11662113c-.04887817-.42082504-.35902055-.76196299-.76398144-.85696816l-.1126697-.01968298zm0-3.25c-.69035594 0-1.25.55964406-1.25 1.25s.55964406 1.25 1.25 1.25 1.25-.55964406 1.25-1.25-.55964406-1.25-1.25-1.25z" fill-rule="evenodd"/></symbol><symbol id="icon-institution" viewBox="0 0 18 18"><path d="m7 16.9998189v-2.0003623h4v2.0003623h2v-3.0005434h-8v3.0005434zm-3-10.00181122h-1.52632364c-.27614237 0-.5-.22389817-.5-.50009056 0-.13995446.05863589-.27350497.16166338-.36820841l1.23156713-1.13206327h-2.36690687v12.00217346h3v-2.0003623h-3v-1.0001811h3v-1.0001811h1v-4.00072448h-1zm10 0v2.00036224h-1v4.00072448h1v1.0001811h3v1.0001811h-3v2.0003623h3v-12.00217346h-2.3695309l1.2315671 1.13206327c.2033191.186892.2166633.50325042.0298051.70660631-.0946863.10304615-.2282126.16169266-.3681417.16169266zm3-3.00054336c.5522847 0 1 .44779634 1 1.00018112v13.00235456h-18v-13.00235456c0-.55238478.44771525-1.00018112 1-1.00018112h3.45499992l4.20535144-3.86558216c.19129876-.17584288.48537447-.17584288.67667324 0l4.2053514 3.86558216zm-4 3.00054336h-8v1.00018112h8zm-2 6.00108672h1v-4.00072448h-1zm-1 0v-4.00072448h-2v4.00072448zm-3 0v-4.00072448h-1v4.00072448zm8-4.00072448c.5522847 0 1 .44779634 1 1.00018112v2.00036226h-2v-2.00036226c0-.55238478.4477153-1.00018112 1-1.00018112zm-12 0c.55228475 0 1 .44779634 1 1.00018112v2.00036226h-2v-2.00036226c0-.55238478.44771525-1.00018112 1-1.00018112zm5.99868798-7.81907007-5.24205601 4.81852671h10.48411203zm.00131202 3.81834559c-.55228475 0-1-.44779634-1-1.00018112s.44771525-1.00018112 1-1.00018112 1 .44779634 1 1.00018112-.44771525 1.00018112-1 1.00018112zm-1 11.00199236v1.0001811h2v-1.0001811z" fill-rule="evenodd"/></symbol><symbol id="icon-location" viewBox="0 0 18 18"><path d="m9.39521328 16.2688008c.79596342-.7770119 1.59208152-1.6299956 2.33285652-2.5295081 1.4020032-1.7024324 2.4323601-3.3624519 2.9354918-4.871847.2228715-.66861448.3364384-1.29323246.3364384-1.8674457 0-3.3137085-2.6862915-6-6-6-3.36356866 0-6 2.60156856-6 6 0 .57421324.11356691 1.19883122.3364384 1.8674457.50313169 1.5093951 1.53348863 3.1694146 2.93549184 4.871847.74077492.8995125 1.53689309 1.7524962 2.33285648 2.5295081.13694479.1336842.26895677.2602648.39521328.3793207.12625651-.1190559.25826849-.2456365.39521328-.3793207zm-.39521328 1.7311992s-7-6-7-11c0-4 3.13400675-7 7-7 3.8659932 0 7 3.13400675 7 7 0 5-7 11-7 11zm0-8c-1.65685425 0-3-1.34314575-3-3s1.34314575-3 3-3c1.6568542 0 3 1.34314575 3 3s-1.3431458 3-3 3zm0-1c1.1045695 0 2-.8954305 2-2s-.8954305-2-2-2-2 .8954305-2 2 .8954305 2 2 2z" fill-rule="evenodd"/></symbol><symbol id="icon-minus" viewBox="0 0 16 16"><path d="m2.00087166 7h11.99825664c.5527662 0 1.0008717.44386482 1.0008717 1 0 .55228475-.4446309 1-1.0008717 1h-11.99825664c-.55276616 0-1.00087166-.44386482-1.00087166-1 0-.55228475.44463086-1 1.00087166-1z" fill-rule="evenodd"/></symbol><symbol id="icon-newsletter" viewBox="0 0 18 18"><path d="m9 11.8482489 2-1.1428571v-1.7053918h-4v1.7053918zm-3-1.7142857v-2.1339632h6v2.1339632l3-1.71428574v-6.41967746h-12v6.41967746zm10-5.3839632 1.5299989.95624934c.2923814.18273835.4700011.50320827.4700011.8479983v8.44575236c0 1.1045695-.8954305 2-2 2h-14c-1.1045695 0-2-.8954305-2-2v-8.44575236c0-.34479003.1776197-.66525995.47000106-.8479983l1.52999894-.95624934v-2.75c0-.55228475.44771525-1 1-1h12c.5522847 0 1 .44771525 1 1zm0 1.17924764v3.07075236l-7 4-7-4v-3.07075236l-1 .625v8.44575236c0 .5522847.44771525 1 1 1h14c.5522847 0 1-.4477153 1-1v-8.44575236zm-10-1.92924764h6v1h-6zm-1 2h8v1h-8z" fill-rule="evenodd"/></symbol><symbol id="icon-orcid" viewBox="0 0 18 18"><path d="m9 1c4.418278 0 8 3.581722 8 8s-3.581722 8-8 8-8-3.581722-8-8 3.581722-8 8-8zm-2.90107518 5.2732337h-1.41865256v7.1712107h1.41865256zm4.55867178.02508949h-2.99247027v7.14612121h2.91062487c.7673039 0 1.4476365-.1483432 2.0410182-.445034s1.0511995-.7152915 1.3734671-1.2558144c.3222677-.540523.4833991-1.1603247.4833991-1.85942385 0-.68545815-.1602789-1.30270225-.4808414-1.85175082-.3205625-.54904856-.7707074-.97532211-1.3504481-1.27883343-.5797408-.30351132-1.2413173-.45526471-1.9847495-.45526471zm-.1892674 1.07933542c.7877654 0 1.4143875.22336734 1.8798852.67010873.4654977.44674138.698243 1.05546001.698243 1.82617415 0 .74343221-.2310402 1.34447791-.6931277 1.80315511-.4620874.4586773-1.0750688.6880124-1.8389625.6880124h-1.46810075v-4.98745039zm-5.08652545-3.71099194c-.21825533 0-.410525.08444276-.57681478.25333081-.16628977.16888806-.24943341.36245684-.24943341.58071218 0 .22345188.08314364.41961891.24943341.58850696.16628978.16888806.35855945.25333082.57681478.25333082.233845 0 .43390938-.08314364.60019916-.24943342.16628978-.16628977.24943342-.36375592.24943342-.59240436 0-.233845-.08314364-.43131115-.24943342-.59240437s-.36635416-.24163862-.60019916-.24163862z" fill-rule="evenodd"/></symbol><symbol id="icon-plus" viewBox="0 0 16 16"><path d="m2.00087166 7h4.99912834v-4.99912834c0-.55276616.44386482-1.00087166 1-1.00087166.55228475 0 1 .44463086 1 1.00087166v4.99912834h4.9991283c.5527662 0 1.0008717.44386482 1.0008717 1 0 .55228475-.4446309 1-1.0008717 1h-4.9991283v4.9991283c0 .5527662-.44386482 1.0008717-1 1.0008717-.55228475 0-1-.4446309-1-1.0008717v-4.9991283h-4.99912834c-.55276616 0-1.00087166-.44386482-1.00087166-1 0-.55228475.44463086-1 1.00087166-1z" fill-rule="evenodd"/></symbol><symbol id="icon-print" viewBox="0 0 18 18"><path d="m16.0049107 5h-14.00982141c-.54941618 0-.99508929.4467783-.99508929.99961498v6.00077002c0 .5570958.44271433.999615.99508929.999615h1.00491071v-3h12v3h1.0049107c.5494162 0 .9950893-.4467783.9950893-.999615v-6.00077002c0-.55709576-.4427143-.99961498-.9950893-.99961498zm-2.0049107-1v-2.00208688c0-.54777062-.4519464-.99791312-1.0085302-.99791312h-7.9829396c-.55661731 0-1.0085302.44910695-1.0085302.99791312v2.00208688zm1 10v2.0018986c0 1.103521-.9019504 1.9981014-2.0085302 1.9981014h-7.9829396c-1.1092806 0-2.0085302-.8867064-2.0085302-1.9981014v-2.0018986h-1.00491071c-1.10185739 0-1.99508929-.8874333-1.99508929-1.999615v-6.00077002c0-1.10435686.8926228-1.99961498 1.99508929-1.99961498h1.00491071v-2.00208688c0-1.10341695.90195036-1.99791312 2.0085302-1.99791312h7.9829396c1.1092806 0 2.0085302.89826062 2.0085302 1.99791312v2.00208688h1.0049107c1.1018574 0 1.9950893.88743329 1.9950893 1.99961498v6.00077002c0 1.1043569-.8926228 1.999615-1.9950893 1.999615zm-1-3h-10v5.0018986c0 .5546075.44702548.9981014 1.0085302.9981014h7.9829396c.5565964 0 1.0085302-.4491701 1.0085302-.9981014zm-9 1h8v1h-8zm0 2h5v1h-5zm9-5c-.5522847 0-1-.44771525-1-1s.4477153-1 1-1 1 .44771525 1 1-.4477153 1-1 1z" fill-rule="evenodd"/></symbol><symbol id="icon-search" viewBox="0 0 22 22"><path d="M21.697 20.261a1.028 1.028 0 01.01 1.448 1.034 1.034 0 01-1.448-.01l-4.267-4.267A9.812 9.811 0 010 9.812a9.812 9.811 0 1117.43 6.182zM9.812 18.222A8.41 8.41 0 109.81 1.403a8.41 8.41 0 000 16.82z" fill-rule="evenodd"/></symbol><symbol id="icon-social-facebook" viewBox="0 0 24 24"><path d="m6.00368507 20c-1.10660471 0-2.00368507-.8945138-2.00368507-1.9940603v-12.01187942c0-1.10128908.89451376-1.99406028 1.99406028-1.99406028h12.01187942c1.1012891 0 1.9940603.89451376 1.9940603 1.99406028v12.01187942c0 1.1012891-.88679 1.9940603-2.0032184 1.9940603h-2.9570132v-6.1960818h2.0797387l.3114113-2.414723h-2.39115v-1.54164807c0-.69911803.1941355-1.1755439 1.1966615-1.1755439l1.2786739-.00055875v-2.15974763l-.2339477-.02492088c-.3441234-.03134957-.9500153-.07025255-1.6293054-.07025255-1.8435726 0-3.1057323 1.12531866-3.1057323 3.19187953v1.78079225h-2.0850778v2.414723h2.0850778v6.1960818z" fill-rule="evenodd"/></symbol><symbol id="icon-social-twitter" viewBox="0 0 24 24"><path d="m18.8767135 6.87445248c.7638174-.46908424 1.351611-1.21167363 1.6250764-2.09636345-.7135248.43394112-1.50406.74870123-2.3464594.91677702-.6695189-.73342162-1.6297913-1.19486605-2.6922204-1.19486605-2.0399895 0-3.6933555 1.69603749-3.6933555 3.78628909 0 .29642457.0314329.58673729.0942985.8617704-3.06469922-.15890802-5.78835241-1.66547825-7.60988389-3.9574208-.3174714.56076194-.49978171 1.21167363-.49978171 1.90536824 0 1.31404706.65223085 2.47224203 1.64236444 3.15218497-.60350999-.0198635-1.17401554-.1925232-1.67222562-.47366811v.04583885c0 1.83355406 1.27302891 3.36609966 2.96411421 3.71294696-.31118484.0886217-.63651445.1329326-.97441718.1329326-.2357461 0-.47149219-.0229194-.69466516-.0672303.47149219 1.5065703 1.83253297 2.6036468 3.44975116 2.632678-1.2651707 1.0160946-2.85724264 1.6196394-4.5891906 1.6196394-.29861172 0-.59093688-.0152796-.88011875-.0504227 1.63450624 1.0726291 3.57548241 1.6990934 5.66104951 1.6990934 6.79263079 0 10.50641749-5.7711113 10.50641749-10.7751859l-.0094298-.48894775c.7229547-.53478659 1.3516109-1.20250585 1.8419628-1.96190282-.6632323.30100846-1.3751855.50422736-2.1217148.59590507z" fill-rule="evenodd"/></symbol><symbol id="icon-social-youtube" viewBox="0 0 24 24"><path d="m10.1415 14.3973208-.0005625-5.19318431 4.863375 2.60554491zm9.963-7.92753362c-.6845625-.73643756-1.4518125-.73990314-1.803375-.7826454-2.518875-.18714178-6.2971875-.18714178-6.2971875-.18714178-.007875 0-3.7861875 0-6.3050625.18714178-.352125.04274226-1.1188125.04620784-1.8039375.7826454-.5394375.56084773-.7149375 1.8344515-.7149375 1.8344515s-.18 1.49597903-.18 2.99138042v1.4024082c0 1.495979.18 2.9913804.18 2.9913804s.1755 1.2736038.7149375 1.8344515c.685125.7364376 1.5845625.7133337 1.9850625.7901542 1.44.1420891 6.12.1859866 6.12.1859866s3.78225-.005776 6.301125-.1929178c.3515625-.0433198 1.1188125-.0467854 1.803375-.783223.5394375-.5608477.7155-1.8344515.7155-1.8344515s.18-1.4954014.18-2.9913804v-1.4024082c0-1.49540139-.18-2.99138042-.18-2.99138042s-.1760625-1.27360377-.7155-1.8344515z" fill-rule="evenodd"/></symbol><symbol id="icon-subject-medicine" viewBox="0 0 18 18"><path d="m12.5 8h-6.5c-1.65685425 0-3 1.34314575-3 3v1c0 1.6568542 1.34314575 3 3 3h1v-2h-.5c-.82842712 0-1.5-.6715729-1.5-1.5s.67157288-1.5 1.5-1.5h1.5 2 1 2c1.6568542 0 3-1.34314575 3-3v-1c0-1.65685425-1.3431458-3-3-3h-2v2h1.5c.8284271 0 1.5.67157288 1.5 1.5s-.6715729 1.5-1.5 1.5zm-5.5-1v-1h-3.5c-1.38071187 0-2.5-1.11928813-2.5-2.5s1.11928813-2.5 2.5-2.5h1.02786405c.46573528 0 .92507448.10843528 1.34164078.31671843l1.13382424.56691212c.06026365-1.05041141.93116291-1.88363055 1.99667093-1.88363055 1.1045695 0 2 .8954305 2 2h2c2.209139 0 4 1.790861 4 4v1c0 2.209139-1.790861 4-4 4h-2v1h2c1.1045695 0 2 .8954305 2 2s-.8954305 2-2 2h-2c0 1.1045695-.8954305 2-2 2s-2-.8954305-2-2h-1c-2.209139 0-4-1.790861-4-4v-1c0-2.209139 1.790861-4 4-4zm0-2v-2.05652691c-.14564246-.03538148-.28733393-.08714006-.42229124-.15461871l-1.15541752-.57770876c-.27771087-.13885544-.583937-.21114562-.89442719-.21114562h-1.02786405c-.82842712 0-1.5.67157288-1.5 1.5s.67157288 1.5 1.5 1.5zm4 1v1h1.5c.2761424 0 .5-.22385763.5-.5s-.2238576-.5-.5-.5zm-1 1v-5c0-.55228475-.44771525-1-1-1s-1 .44771525-1 1v5zm-2 4v5c0 .5522847.44771525 1 1 1s1-.4477153 1-1v-5zm3 2v2h2c.5522847 0 1-.4477153 1-1s-.4477153-1-1-1zm-4-1v-1h-.5c-.27614237 0-.5.2238576-.5.5s.22385763.5.5.5zm-3.5-9h1c.27614237 0 .5.22385763.5.5s-.22385763.5-.5.5h-1c-.27614237 0-.5-.22385763-.5-.5s.22385763-.5.5-.5z" fill-rule="evenodd"/></symbol><symbol id="icon-success" viewBox="0 0 18 18"><path d="m9 0c4.9705627 0 9 4.02943725 9 9 0 4.9705627-4.0294373 9-9 9-4.97056275 0-9-4.0294373-9-9 0-4.97056275 4.02943725-9 9-9zm3.4860198 4.98163161-4.71802968 5.50657859-2.62834168-2.02300024c-.42862421-.36730544-1.06564993-.30775346-1.42283677.13301307-.35718685.44076653-.29927542 1.0958383.12934879 1.46314377l3.40735508 2.7323063c.42215801.3385221 1.03700951.2798252 1.38749189-.1324571l5.38450527-6.33394549c.3613513-.43716226.3096573-1.09278382-.115462-1.46437175-.4251192-.37158792-1.0626796-.31842941-1.4240309.11873285z" fill-rule="evenodd"/></symbol><symbol id="icon-table" viewBox="0 0 18 18"><path d="m16.0049107 2c1.1018574 0 1.9950893.89706013 1.9950893 2.00585866v9.98828264c0 1.1078052-.8926228 2.0058587-1.9950893 2.0058587l-4.0059107-.001.001.001h-1l-.001-.001h-5l.001.001h-1l-.001-.001-3.00391071.001c-1.10185739 0-1.99508929-.8970601-1.99508929-2.0058587v-9.98828264c0-1.10780515.8926228-2.00585866 1.99508929-2.00585866zm-11.0059107 5h-3.999v6.9941413c0 .5572961.44630695 1.0058587.99508929 1.0058587h3.00391071zm6 0h-5v8h5zm5.0059107-4h-4.0059107v3h5.001v1h-5.001v7.999l4.0059107.001c.5487152 0 .9950893-.4488783.9950893-1.0058587v-9.98828264c0-.55729607-.446307-1.00585866-.9950893-1.00585866zm-12.5049107 9c.27614237 0 .5.2238576.5.5s-.22385763.5-.5.5h-1c-.27614237 0-.5-.2238576-.5-.5s.22385763-.5.5-.5zm12 0c.2761424 0 .5.2238576.5.5s-.2238576.5-.5.5h-2c-.2761424 0-.5-.2238576-.5-.5s.2238576-.5.5-.5zm-6 0c.27614237 0 .5.2238576.5.5s-.22385763.5-.5.5h-2c-.27614237 0-.5-.2238576-.5-.5s.22385763-.5.5-.5zm-6-2c.27614237 0 .5.2238576.5.5s-.22385763.5-.5.5h-1c-.27614237 0-.5-.2238576-.5-.5s.22385763-.5.5-.5zm12 0c.2761424 0 .5.2238576.5.5s-.2238576.5-.5.5h-2c-.2761424 0-.5-.2238576-.5-.5s.2238576-.5.5-.5zm-6 0c.27614237 0 .5.2238576.5.5s-.22385763.5-.5.5h-2c-.27614237 0-.5-.2238576-.5-.5s.22385763-.5.5-.5zm-6-2c.27614237 0 .5.22385763.5.5s-.22385763.5-.5.5h-1c-.27614237 0-.5-.22385763-.5-.5s.22385763-.5.5-.5zm12 0c.2761424 0 .5.22385763.5.5s-.2238576.5-.5.5h-2c-.2761424 0-.5-.22385763-.5-.5s.2238576-.5.5-.5zm-6 0c.27614237 0 .5.22385763.5.5s-.22385763.5-.5.5h-2c-.27614237 0-.5-.22385763-.5-.5s.22385763-.5.5-.5zm1.499-5h-5v3h5zm-6 0h-3.00391071c-.54871518 0-.99508929.44887827-.99508929 1.00585866v1.99414134h3.999z" fill-rule="evenodd"/></symbol><symbol id="icon-tick-circle" viewBox="0 0 24 24"><path d="m12 2c5.5228475 0 10 4.4771525 10 10s-4.4771525 10-10 10-10-4.4771525-10-10 4.4771525-10 10-10zm0 1c-4.97056275 0-9 4.02943725-9 9 0 4.9705627 4.02943725 9 9 9 4.9705627 0 9-4.0294373 9-9 0-4.97056275-4.0294373-9-9-9zm4.2199868 5.36606669c.3613514-.43716226.9989118-.49032077 1.424031-.11873285s.4768133 1.02720949.115462 1.46437175l-6.093335 6.94397871c-.3622945.4128716-.9897871.4562317-1.4054264.0971157l-3.89719065-3.3672071c-.42862421-.3673054-.48653564-1.0223772-.1293488-1.4631437s.99421256-.5003185 1.42283677-.1330131l3.11097438 2.6987741z" fill-rule="evenodd"/></symbol><symbol id="icon-tick" viewBox="0 0 16 16"><path d="m6.76799012 9.21106946-3.1109744-2.58349728c-.42862421-.35161617-1.06564993-.29460792-1.42283677.12733148s-.29927541 1.04903009.1293488 1.40064626l3.91576307 3.23873978c.41034319.3393961 1.01467563.2976897 1.37450571-.0948578l6.10568327-6.660841c.3613513-.41848908.3096572-1.04610608-.115462-1.4018218-.4251192-.35571573-1.0626796-.30482786-1.424031.11366122z" fill-rule="evenodd"/></symbol><symbol id="icon-update" viewBox="0 0 18 18"><path d="m1 13v1c0 .5522847.44771525 1 1 1h14c.5522847 0 1-.4477153 1-1v-1h-1v-10h-14v10zm16-1h1v2c0 1.1045695-.8954305 2-2 2h-14c-1.1045695 0-2-.8954305-2-2v-2h1v-9c0-.55228475.44771525-1 1-1h14c.5522847 0 1 .44771525 1 1zm-1 0v1h-4.5857864l-1 1h-2.82842716l-1-1h-4.58578644v-1h5l1 1h2l1-1zm-13-8h12v7h-12zm1 1v5h10v-5zm1 1h4v1h-4zm0 2h4v1h-4z" fill-rule="evenodd"/></symbol><symbol id="icon-upload" viewBox="0 0 18 18"><path d="m10.0046024 0c.5497429 0 1.3179837.32258606 1.707238.71184039l4.5763192 4.57631922c.3931386.39313859.7118404 1.16760135.7118404 1.71431368v8.98899651c0 1.1092806-.8945138 2.0085302-1.9940603 2.0085302h-12.01187942c-1.10128908 0-1.99406028-.8926228-1.99406028-1.9950893v-14.00982141c0-1.10185739.88743329-1.99508929 1.99961498-1.99508929zm0 1h-7.00498742c-.55709576 0-.99961498.44271433-.99961498.99508929v14.00982141c0 .5500396.44491393.9950893.99406028.9950893h12.01187942c.5463747 0 .9940603-.4506622.9940603-1.0085302v-8.98899651c0-.28393444-.2150684-.80332809-.4189472-1.0072069l-4.5763192-4.57631922c-.2038461-.20384606-.718603-.41894717-1.0001312-.41894717zm-1.85576936 4.14572769c.19483374-.19483375.51177826-.19377714.70556874.00001334l2.59099082 2.59099079c.1948411.19484112.1904373.51514474.0027906.70279143-.1932998.19329987-.5046517.19237083-.7001856-.00692852l-1.74638687-1.7800176v6.14827687c0 .2717771-.23193359.492096-.5.492096-.27614237 0-.5-.216372-.5-.492096v-6.14827641l-1.74627892 1.77990922c-.1933927.1971171-.51252214.19455839-.70016883.0069117-.19329987-.19329988-.19100584-.50899493.00277731-.70277808z" fill-rule="evenodd"/></symbol><symbol id="icon-video" viewBox="0 0 18 18"><path d="m16.0049107 2c1.1018574 0 1.9950893.89706013 1.9950893 2.00585866v9.98828264c0 1.1078052-.8926228 2.0058587-1.9950893 2.0058587h-14.00982141c-1.10185739 0-1.99508929-.8970601-1.99508929-2.0058587v-9.98828264c0-1.10780515.8926228-2.00585866 1.99508929-2.00585866zm0 1h-14.00982141c-.54871518 0-.99508929.44887827-.99508929 1.00585866v9.98828264c0 .5572961.44630695 1.0058587.99508929 1.0058587h14.00982141c.5487152 0 .9950893-.4488783.9950893-1.0058587v-9.98828264c0-.55729607-.446307-1.00585866-.9950893-1.00585866zm-8.30912922 2.24944486 4.60460462 2.73982242c.9365543.55726659.9290753 1.46522435 0 2.01804082l-4.60460462 2.7398224c-.93655425.5572666-1.69578148.1645632-1.69578148-.8937585v-5.71016863c0-1.05087579.76670616-1.446575 1.69578148-.89375851zm-.67492769.96085624v5.5750128c0 .2995102-.10753745.2442517.16578928.0847713l4.58452283-2.67497259c.3050619-.17799716.3051624-.21655446 0-.39461026l-4.58452283-2.67497264c-.26630747-.15538481-.16578928-.20699944-.16578928.08477139z" fill-rule="evenodd"/></symbol><symbol id="icon-warning" viewBox="0 0 18 18"><path d="m9 11.75c.69035594 0 1.25.5596441 1.25 1.25s-.55964406 1.25-1.25 1.25-1.25-.5596441-1.25-1.25.55964406-1.25 1.25-1.25zm.41320045-7.75c.55228475 0 1.00000005.44771525 1.00000005 1l-.0034543.08304548-.3333333 4c-.043191.51829212-.47645714.91695452-.99654578.91695452h-.15973424c-.52008864 0-.95335475-.3986624-.99654576-.91695452l-.33333333-4c-.04586475-.55037702.36312325-1.03372649.91350028-1.07959124l.04148683-.00259031zm-.41320045 14c-4.97056275 0-9-4.0294373-9-9 0-4.97056275 4.02943725-9 9-9 4.9705627 0 9 4.02943725 9 9 0 4.9705627-4.0294373 9-9 9z" fill-rule="evenodd"/></symbol><symbol id="icon-checklist-banner" viewBox="0 0 56.69 56.69"><path style="fill:none" d="M0 0h56.69v56.69H0z"/><clipPath id="b"><use xlink:href="#a" style="overflow:visible"/></clipPath><path d="M21.14 34.46c0-6.77 5.48-12.26 12.24-12.26s12.24 5.49 12.24 12.26-5.48 12.26-12.24 12.26c-6.76-.01-12.24-5.49-12.24-12.26zm19.33 10.66 10.23 9.22s1.21 1.09 2.3-.12l2.09-2.32s1.09-1.21-.12-2.3l-10.23-9.22m-19.29-5.92c0-4.38 3.55-7.94 7.93-7.94s7.93 3.55 7.93 7.94c0 4.38-3.55 7.94-7.93 7.94-4.38-.01-7.93-3.56-7.93-7.94zm17.58 12.99 4.14-4.81" style="clip-path:url(#b);fill:none;stroke:#01324b;stroke-width:2;stroke-linecap:round"/><path d="M8.26 9.75H28.6M8.26 15.98H28.6m-20.34 6.2h12.5m14.42-5.2V4.86s0-2.93-2.93-2.93H4.13s-2.93 0-2.93 2.93v37.57s0 2.93 2.93 2.93h15.01M8.26 9.75H28.6M8.26 15.98H28.6m-20.34 6.2h12.5" style="clip-path:url(#b);fill:none;stroke:#01324b;stroke-width:2;stroke-linecap:round;stroke-linejoin:round"/></symbol><symbol id="icon-chevron-down" viewBox="0 0 16 16"><path d="m5.58578644 3-3.29289322-3.29289322c-.39052429-.39052429-.39052429-1.02368927 0-1.41421356s1.02368927-.39052429 1.41421356 0l4 4c.39052429.39052429.39052429 1.02368927 0 1.41421356l-4 4c-.39052429.39052429-1.02368927.39052429-1.41421356 0s-.39052429-1.02368927 0-1.41421356z" fill-rule="evenodd" transform="matrix(0 1 -1 0 11 1)"/></symbol><symbol id="icon-eds-i-arrow-right-medium" viewBox="0 0 24 24"><path d="m12.728 3.293 7.98 7.99a.996.996 0 0 1 .281.561l.011.157c0 .32-.15.605-.384.788l-7.908 7.918a1 1 0 0 1-1.416-1.414L17.576 13H4a1 1 0 0 1 0-2h13.598l-6.285-6.293a1 1 0 0 1-.082-1.32l.083-.095a1 1 0 0 1 1.414.001Z"/></symbol><symbol id="icon-eds-i-chevron-down-medium" viewBox="0 0 16 16"><path d="m2.00087166 7h4.99912834v-4.99912834c0-.55276616.44386482-1.00087166 1-1.00087166.55228475 0 1 .44463086 1 1.00087166v4.99912834h4.9991283c.5527662 0 1.0008717.44386482 1.0008717 1 0 .55228475-.4446309 1-1.0008717 1h-4.9991283v4.9991283c0 .5527662-.44386482 1.0008717-1 1.0008717-.55228475 0-1-.4446309-1-1.0008717v-4.9991283h-4.99912834c-.55276616 0-1.00087166-.44386482-1.00087166-1 0-.55228475.44463086-1 1.00087166-1z" fill-rule="evenodd"/></symbol><symbol id="icon-eds-i-chevron-down-small" viewBox="0 0 16 16"><path d="M13.692 5.278a1 1 0 0 1 .03 1.414L9.103 11.51a1.491 1.491 0 0 1-2.188.019L2.278 6.692a1 1 0 0 1 1.444-1.384L8 9.771l4.278-4.463a1 1 0 0 1 1.318-.111l.096.081Z"/></symbol><symbol id="icon-eds-i-chevron-right-medium" viewBox="0 0 10 10"><path d="m5.96738168 4.70639573 2.39518594-2.41447274c.37913917-.38219212.98637524-.38972225 1.35419292-.01894278.37750606.38054586.37784436.99719163-.00013556 1.37821513l-4.03074001 4.06319683c-.37758093.38062133-.98937525.38100976-1.367372-.00003075l-4.03091981-4.06337806c-.37759778-.38063832-.38381821-.99150444-.01600053-1.3622839.37750607-.38054587.98772445-.38240057 1.37006824.00302197l2.39538588 2.4146743.96295325.98624457z" fill-rule="evenodd" transform="matrix(0 -1 1 0 0 10)"/></symbol><symbol id="icon-eds-i-chevron-right-small" viewBox="0 0 10 10"><path d="m5.96738168 4.70639573 2.39518594-2.41447274c.37913917-.38219212.98637524-.38972225 1.35419292-.01894278.37750606.38054586.37784436.99719163-.00013556 1.37821513l-4.03074001 4.06319683c-.37758093.38062133-.98937525.38100976-1.367372-.00003075l-4.03091981-4.06337806c-.37759778-.38063832-.38381821-.99150444-.01600053-1.3622839.37750607-.38054587.98772445-.38240057 1.37006824.00302197l2.39538588 2.4146743.96295325.98624457z" fill-rule="evenodd" transform="matrix(0 -1 1 0 0 10)"/></symbol><symbol id="icon-eds-i-chevron-up-medium" viewBox="0 0 16 16"><path d="m2.00087166 7h11.99825664c.5527662 0 1.0008717.44386482 1.0008717 1 0 .55228475-.4446309 1-1.0008717 1h-11.99825664c-.55276616 0-1.00087166-.44386482-1.00087166-1 0-.55228475.44463086-1 1.00087166-1z" fill-rule="evenodd"/></symbol><symbol id="icon-eds-i-close-medium" viewBox="0 0 16 16"><path d="m2.29679575 12.2772478c-.39658757.3965876-.39438847 1.0328109-.00062148 1.4265779.39651227.3965123 1.03246768.3934888 1.42657791-.0006214l4.27724782-4.27724787 4.2772478 4.27724787c.3965876.3965875 1.0328109.3943884 1.4265779.0006214.3965123-.3965122.3934888-1.0324677-.0006214-1.4265779l-4.27724787-4.2772478 4.27724787-4.27724782c.3965875-.39658757.3943884-1.03281091.0006214-1.42657791-.3965122-.39651226-1.0324677-.39348875-1.4265779.00062148l-4.2772478 4.27724782-4.27724782-4.27724782c-.39658757-.39658757-1.03281091-.39438847-1.42657791-.00062148-.39651226.39651227-.39348875 1.03246768.00062148 1.42657791l4.27724782 4.27724782z" fill-rule="evenodd"/></symbol><symbol id="icon-eds-i-download-medium" viewBox="0 0 16 16"><path d="m12.9975267 12.999368c.5467123 0 1.0024733.4478567 1.0024733 1.000316 0 .5563109-.4488226 1.000316-1.0024733 1.000316h-9.99505341c-.54671233 0-1.00247329-.4478567-1.00247329-1.000316 0-.5563109.44882258-1.000316 1.00247329-1.000316zm-4.9975267-11.999368c.55228475 0 1 .44497754 1 .99589209v6.80214418l2.4816273-2.48241149c.3928222-.39294628 1.0219732-.4006883 1.4030652-.01947579.3911302.39125371.3914806 1.02525073-.0001404 1.41699553l-4.17620792 4.17752758c-.39120769.3913313-1.02508144.3917306-1.41671995-.0000316l-4.17639421-4.17771394c-.39122513-.39134876-.39767006-1.01940351-.01657797-1.40061601.39113012-.39125372 1.02337105-.3931606 1.41951349.00310701l2.48183446 2.48261871v-6.80214418c0-.55001601.44386482-.99589209 1-.99589209z" fill-rule="evenodd"/></symbol><symbol id="icon-eds-i-info-filled-medium" viewBox="0 0 18 18"><path d="m9 0c4.9705627 0 9 4.02943725 9 9 0 4.9705627-4.0294373 9-9 9-4.97056275 0-9-4.0294373-9-9 0-4.97056275 4.02943725-9 9-9zm0 7h-1.5l-.11662113.00672773c-.49733868.05776511-.88337887.48043643-.88337887.99327227 0 .47338693.32893365.86994729.77070917.97358929l.1126697.01968298.11662113.00672773h.5v3h-.5l-.11662113.0067277c-.42082504.0488782-.76196299.3590206-.85696816.7639815l-.01968298.1126697-.00672773.1166211.00672773.1166211c.04887817.4208251.35902055.761963.76398144.8569682l.1126697.019683.11662113.0067277h3l.1166211-.0067277c.4973387-.0577651.8833789-.4804365.8833789-.9932723 0-.4733869-.3289337-.8699473-.7707092-.9735893l-.1126697-.019683-.1166211-.0067277h-.5v-4l-.00672773-.11662113c-.04887817-.42082504-.35902055-.76196299-.76398144-.85696816l-.1126697-.01968298zm0-3.25c-.69035594 0-1.25.55964406-1.25 1.25s.55964406 1.25 1.25 1.25 1.25-.55964406 1.25-1.25-.55964406-1.25-1.25-1.25z" fill-rule="evenodd"/></symbol><symbol id="icon-eds-i-mail-medium" viewBox="0 0 24 24"><path d="m19.462 0c1.413 0 2.538 1.184 2.538 2.619v12.762c0 1.435-1.125 2.619-2.538 2.619h-16.924c-1.413 0-2.538-1.184-2.538-2.619v-12.762c0-1.435 1.125-2.619 2.538-2.619zm.538 5.158-7.378 6.258a2.549 2.549 0 0 1 -3.253-.008l-7.369-6.248v10.222c0 .353.253.619.538.619h16.924c.285 0 .538-.266.538-.619zm-.538-3.158h-16.924c-.264 0-.5.228-.534.542l8.65 7.334c.2.165.492.165.684.007l8.656-7.342-.001-.025c-.044-.3-.274-.516-.531-.516z"/></symbol><symbol id="icon-eds-i-menu-medium" viewBox="0 0 24 24"><path d="M21 4a1 1 0 0 1 0 2H3a1 1 0 1 1 0-2h18Zm-4 7a1 1 0 0 1 0 2H3a1 1 0 0 1 0-2h14Zm4 7a1 1 0 0 1 0 2H3a1 1 0 0 1 0-2h18Z"/></symbol><symbol id="icon-eds-i-search-medium" viewBox="0 0 24 24"><path d="M11 1c5.523 0 10 4.477 10 10 0 2.4-.846 4.604-2.256 6.328l3.963 3.965a1 1 0 0 1-1.414 1.414l-3.965-3.963A9.959 9.959 0 0 1 11 21C5.477 21 1 16.523 1 11S5.477 1 11 1Zm0 2a8 8 0 1 0 0 16 8 8 0 0 0 0-16Z"/></symbol><symbol id="icon-eds-i-user-single-medium" viewBox="0 0 24 24"><path d="M12 1a5 5 0 1 1 0 10 5 5 0 0 1 0-10Zm0 2a3 3 0 1 0 0 6 3 3 0 0 0 0-6Zm-.406 9.008a8.965 8.965 0 0 1 6.596 2.494A9.161 9.161 0 0 1 21 21.025V22a1 1 0 0 1-1 1H4a1 1 0 0 1-1-1v-.985c.05-4.825 3.815-8.777 8.594-9.007Zm.39 1.992-.299.006c-3.63.175-6.518 3.127-6.678 6.775L5 21h13.998l-.009-.268a7.157 7.157 0 0 0-1.97-4.573l-.214-.213A6.967 6.967 0 0 0 11.984 14Z"/></symbol><symbol id="icon-eds-i-warning-filled-medium" viewBox="0 0 18 18"><path d="m9 11.75c.69035594 0 1.25.5596441 1.25 1.25s-.55964406 1.25-1.25 1.25-1.25-.5596441-1.25-1.25.55964406-1.25 1.25-1.25zm.41320045-7.75c.55228475 0 1.00000005.44771525 1.00000005 1l-.0034543.08304548-.3333333 4c-.043191.51829212-.47645714.91695452-.99654578.91695452h-.15973424c-.52008864 0-.95335475-.3986624-.99654576-.91695452l-.33333333-4c-.04586475-.55037702.36312325-1.03372649.91350028-1.07959124l.04148683-.00259031zm-.41320045 14c-4.97056275 0-9-4.0294373-9-9 0-4.97056275 4.02943725-9 9-9 4.9705627 0 9 4.02943725 9 9 0 4.9705627-4.0294373 9-9 9z" fill-rule="evenodd"/></symbol><symbol id="icon-expand-image" viewBox="0 0 18 18"><path d="m7.49754099 11.9178212c.38955542-.3895554.38761957-1.0207846-.00290473-1.4113089-.39324695-.3932469-1.02238878-.3918247-1.41130883-.0029047l-4.10273549 4.1027355.00055454-3.5103985c.00008852-.5603185-.44832171-1.006032-1.00155062-1.0059446-.53903074.0000852-.97857527.4487442-.97866268 1.0021075l-.00093318 5.9072465c-.00008751.553948.44841131 1.001882 1.00174994 1.0017946l5.906983-.0009331c.5539233-.0000875 1.00197907-.4486389 1.00206646-1.0018679.00008515-.5390307-.45026621-.9784332-1.00588841-.9783454l-3.51010549.0005545zm3.00571741-5.83449376c-.3895554.38955541-.3876196 1.02078454.0029047 1.41130883.393247.39324696 1.0223888.39182478 1.4113089.00290473l4.1027355-4.10273549-.0005546 3.5103985c-.0000885.56031852.4483217 1.006032 1.0015506 1.00594461.5390308-.00008516.9785753-.44874418.9786627-1.00210749l.0009332-5.9072465c.0000875-.553948-.4484113-1.00188204-1.0017499-1.00179463l-5.906983.00093313c-.5539233.00008751-1.0019791.44863892-1.0020665 1.00186784-.0000852.53903074.4502662.97843325 1.0058884.97834547l3.5101055-.00055449z" fill-rule="evenodd"/></symbol><symbol id="icon-github" viewBox="0 0 100 100"><path fill-rule="evenodd" clip-rule="evenodd" d="M48.854 0C21.839 0 0 22 0 49.217c0 21.756 13.993 40.172 33.405 46.69 2.427.49 3.316-1.059 3.316-2.362 0-1.141-.08-5.052-.08-9.127-13.59 2.934-16.42-5.867-16.42-5.867-2.184-5.704-5.42-7.17-5.42-7.17-4.448-3.015.324-3.015.324-3.015 4.934.326 7.523 5.052 7.523 5.052 4.367 7.496 11.404 5.378 14.235 4.074.404-3.178 1.699-5.378 3.074-6.6-10.839-1.141-22.243-5.378-22.243-24.283 0-5.378 1.94-9.778 5.014-13.2-.485-1.222-2.184-6.275.486-13.038 0 0 4.125-1.304 13.426 5.052a46.97 46.97 0 0 1 12.214-1.63c4.125 0 8.33.571 12.213 1.63 9.302-6.356 13.427-5.052 13.427-5.052 2.67 6.763.97 11.816.485 13.038 3.155 3.422 5.015 7.822 5.015 13.2 0 18.905-11.404 23.06-22.324 24.283 1.78 1.548 3.316 4.481 3.316 9.126 0 6.6-.08 11.897-.08 13.526 0 1.304.89 2.853 3.316 2.364 19.412-6.52 33.405-24.935 33.405-46.691C97.707 22 75.788 0 48.854 0z"/></symbol><symbol id="icon-springer-arrow-left"><path d="M15 7a1 1 0 000-2H3.385l2.482-2.482a.994.994 0 00.02-1.403 1.001 1.001 0 00-1.417 0L.294 5.292a1.001 1.001 0 000 1.416l4.176 4.177a.991.991 0 001.4.016 1 1 0 00-.003-1.42L3.385 7H15z"/></symbol><symbol id="icon-springer-arrow-right"><path d="M1 7a1 1 0 010-2h11.615l-2.482-2.482a.994.994 0 01-.02-1.403 1.001 1.001 0 011.417 0l4.176 4.177a1.001 1.001 0 010 1.416l-4.176 4.177a.991.991 0 01-1.4.016 1 1 0 01.003-1.42L12.615 7H1z"/></symbol><symbol id="icon-submit-open" viewBox="0 0 16 17"><path d="M12 0c1.10457 0 2 .895431 2 2v5c0 .276142-.223858.5-.5.5S13 7.276142 13 7V2c0-.512836-.38604-.935507-.883379-.993272L12 1H6v3c0 1.10457-.89543 2-2 2H1v8c0 .512836.38604.935507.883379.993272L2 15h6.5c.276142 0 .5.223858.5.5s-.223858.5-.5.5H2c-1.104569 0-2-.89543-2-2V5.828427c0-.530433.210714-1.039141.585786-1.414213L4.414214.585786C4.789286.210714 5.297994 0 5.828427 0H12Zm3.41 11.14c.250899.250899.250274.659726 0 .91-.242954.242954-.649606.245216-.9-.01l-1.863671-1.900337.001043 5.869492c0 .356992-.289839.637138-.647372.637138-.347077 0-.647371-.285256-.647371-.637138l-.001043-5.869492L9.5 12.04c-.253166.258042-.649726.260274-.9.01-.242954-.242954-.252269-.657731 0-.91l2.942184-2.951303c.250908-.250909.66127-.252277.91353-.000017L15.41 11.14ZM5 1.413 1.413 5H4c.552285 0 1-.447715 1-1V1.413ZM11 3c.276142 0 .5.223858.5.5s-.223858.5-.5.5H7.5c-.276142 0-.5-.223858-.5-.5s.223858-.5.5-.5H11Zm0 2c.276142 0 .5.223858.5.5s-.223858.5-.5.5H7.5c-.276142 0-.5-.223858-.5-.5s.223858-.5.5-.5H11Z" fill-rule="nonzero"/></symbol></svg> </div> </footer> <div class="c-site-messages message u-hide u-hide-print c-site-messages--nature-briefing c-site-messages--nature-briefing-email-variant c-site-messages--nature-briefing-redesign-2020 sans-serif " data-component-id="nature-briefing-banner" data-component-expirydays="30" data-component-trigger-scroll-percentage="15" data-track="in-view" data-track-action="in-view" data-track-category="nature briefing" data-track-label="Briefing banner visible: Flagship"> <div class="c-site-messages__banner-large"> <div class="c-site-messages__close-container"> <button class="c-site-messages__close" data-track="click" data-track-category="nature briefing" data-track-label="Briefing banner dismiss: Flagship"> <svg width="25px" height="25px" focusable="false" aria-hidden="true" viewBox="0 0 25 25" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Close banner</title> <defs></defs> <g stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <rect opacity="0" x="0" y="0" width="25" height="25"></rect> <path d="M6.29679575,16.2772478 C5.90020818,16.6738354 5.90240728,17.3100587 6.29617427,17.7038257 C6.69268654,18.100338 7.32864195,18.0973145 7.72275218,17.7032043 L12,13.4259564 L16.2772478,17.7032043 C16.6738354,18.0997918 17.3100587,18.0975927 17.7038257,17.7038257 C18.100338,17.3073135 18.0973145,16.671358 17.7032043,16.2772478 L13.4259564,12 L17.7032043,7.72275218 C18.0997918,7.32616461 18.0975927,6.68994127 17.7038257,6.29617427 C17.3073135,5.89966201 16.671358,5.90268552 16.2772478,6.29679575 L12,10.5740436 L7.72275218,6.29679575 C7.32616461,5.90020818 6.68994127,5.90240728 6.29617427,6.29617427 C5.89966201,6.69268654 5.90268552,7.32864195 6.29679575,7.72275218 L10.5740436,12 L6.29679575,16.2772478 Z" fill="#ffffff"></path> </g> </svg> <span class="visually-hidden">Close</span> </button> </div> <div class="c-site-messages__form-container"> <div class="grid grid-12 last"> <div class="grid grid-4"> <img alt="Nature Briefing" src="/static/images/logos/nature-briefing-logo-n150-white-d81c9da3ec.svg" width="250" height="40"> <p class="c-site-messages--nature-briefing__strapline extra-tight-line-height">Sign up for the <em>Nature Briefing</em> newsletter — what matters in science, free to your inbox daily.</p> </div> <div class="grid grid-8 last"> <form action="https://www.nature.com/briefing/briefing" method="post" data-location="banner" data-track="signup_nature_briefing_banner" data-track-action="transmit-form" data-track-category="nature briefing" data-track-label="Briefing banner submit: Flagship"> <input id="briefing-banner-signup-form-input-track-originReferralPoint" type="hidden" name="track_originReferralPoint" value="MainBriefingBanner"> <input id="briefing-banner-signup-form-input-track-formType" type="hidden" name="track_formType" value="DirectEmailBanner"> <input type="hidden" value="false" name="gdpr_tick" id="gdpr_tick_banner"> <input type="hidden" value="false" name="marketing" id="marketing_input_banner"> <input type="hidden" value="false" name="marketing_tick" id="marketing_tick_banner"> <input type="hidden" value="MainBriefingBanner" name="brieferEntryPoint" id="brieferEntryPoint_banner"> <label class="nature-briefing-banner__email-label" for="emailAddress">Email address</label> <div class="nature-briefing-banner__email-wrapper"> <input class="nature-briefing-banner__email-input box-sizing text14" type="email" id="emailAddress" name="emailAddress" value="" placeholder="e.g. jo.smith@university.ac.uk" required data-test-element="briefing-emailbanner-email-input"> <input type="hidden" value="true" name="N:nature_briefing_daily" id="defaultNewsletter_banner"> <button type="submit" class="nature-briefing-banner__submit-button box-sizing text14" data-test-element="briefing-emailbanner-signup-button">Sign up</button> </div> <div class="nature-briefing-banner__checkbox-wrapper grid grid-12 last"> <input class="nature-briefing-banner__checkbox-checkbox" id="gdpr-briefing-banner-checkbox" type="checkbox" name="gdpr" value="true" data-test-element="briefing-emailbanner-gdpr-checkbox" required> <label class="nature-briefing-banner__checkbox-label box-sizing text13 sans-serif block tighten-line-height" for="gdpr-briefing-banner-checkbox">I agree my information will be processed in accordance with the <em>Nature</em> and Springer Nature Limited <a href="https://www.nature.com/info/privacy">Privacy Policy</a>.</label> </div> </form> </div> </div> </div> </div> <div class="c-site-messages__banner-small"> <div class="c-site-messages__close-container"> <button class="c-site-messages__close" data-track="click" data-track-category="nature briefing" data-track-label="Briefing banner dismiss: Flagship"> <svg width="25px" height="25px" focusable="false" aria-hidden="true" viewBox="0 0 25 25" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"> <title>Close banner</title> <defs></defs> <g stroke="none" stroke-width="1" fill="none" fill-rule="evenodd"> <rect opacity="0" x="0" y="0" width="25" height="25"></rect> <path d="M6.29679575,16.2772478 C5.90020818,16.6738354 5.90240728,17.3100587 6.29617427,17.7038257 C6.69268654,18.100338 7.32864195,18.0973145 7.72275218,17.7032043 L12,13.4259564 L16.2772478,17.7032043 C16.6738354,18.0997918 17.3100587,18.0975927 17.7038257,17.7038257 C18.100338,17.3073135 18.0973145,16.671358 17.7032043,16.2772478 L13.4259564,12 L17.7032043,7.72275218 C18.0997918,7.32616461 18.0975927,6.68994127 17.7038257,6.29617427 C17.3073135,5.89966201 16.671358,5.90268552 16.2772478,6.29679575 L12,10.5740436 L7.72275218,6.29679575 C7.32616461,5.90020818 6.68994127,5.90240728 6.29617427,6.29617427 C5.89966201,6.69268654 5.90268552,7.32864195 6.29679575,7.72275218 L10.5740436,12 L6.29679575,16.2772478 Z" fill="#ffffff"></path> </g> </svg> <span class="visually-hidden">Close</span> </button> </div> <div class="c-site-messages__content text14"> <span class="c-site-messages--nature-briefing__strapline strong">Get the most important science stories of the day, free in your inbox.</span> <a class="nature-briefing__link text14 sans-serif" data-track="click" data-track-category="nature briefing" data-track-label="Small-screen banner CTA to site" data-test-element="briefing-banner-link" target="_blank" rel="noreferrer noopener" href="https://www.nature.com/briefing/signup/?brieferEntryPoint=MainBriefingBanner">Sign up for Nature Briefing </a> </div> </div> </div> <noscript> <img hidden src="https://verify.nature.com/verify/nature.png" width="0" height="0" style="display: none" alt=""> </noscript> <script src="//content.readcube.com/ping?doi=10.1038/s41467-018-06743-8&format=js&last_modified=2019-11-13" async></script> </body> </html>

CINXE.COM

Seeded X-ray free-electron laser generating radiation with laser statistical properties | Nature Communications