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menu__item--page-actions-edit"> <span class="minerva-icon minerva-icon--edit"></span> <span>Edit</span> </a> </li> </ul> </nav>  <div id="mw-content-subtitle"></div> </div> <div id="bodyContent" class="content"> <div id="mw-content-text" class="mw-body-content"><script>function mfTempOpenSection(id){var block=document.getElementById("mf-section-"+id);block.className+=" open-block";block.previousSibling.className+=" open-block";}</script><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><section class="mf-section-0" id="mf-section-0"> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">For other uses, see <a href="/wiki/Maser_(disambiguation)" class="mw-disambig" title="Maser (disambiguation)">Maser (disambiguation)</a>.</div> <p>A <b>maser</b> is a device that produces <a href="/wiki/Coherence_(physics)" title="Coherence (physics)">coherent</a> <a href="/wiki/Electromagnetic_wave" class="mw-redirect" title="Electromagnetic wave">electromagnetic waves</a> (<a href="/wiki/Microwaves" class="mw-redirect" title="Microwaves">microwaves</a>), through amplification by <a href="/wiki/Stimulated_emission" title="Stimulated emission">stimulated emission</a>. The term is an acronym for <b>microwave amplification by stimulated emission of radiation</b>. <a href="/wiki/Nikolay_Basov" title="Nikolay Basov">Nikolay Basov</a>, <a href="/wiki/Alexander_Prokhorov" title="Alexander Prokhorov">Alexander Prokhorov</a> and <a href="/wiki/Joseph_Weber" title="Joseph Weber">Joseph Weber</a> introduced the concept of the maser in 1952, and <a href="/wiki/Charles_H._Townes" title="Charles H. Townes">Charles H. Townes</a>, <a href="/wiki/James_P._Gordon" title="James P. Gordon">James P. Gordon</a>, and <a href="/wiki/Herbert_J._Zeiger" class="mw-redirect" title="Herbert J. Zeiger">Herbert J. Zeiger</a> built the first maser at <a href="/wiki/Columbia_University" title="Columbia University">Columbia University</a> in 1953. Townes, Basov and Prokhorov won the 1964 <a href="/wiki/Nobel_Prize_in_Physics" title="Nobel Prize in Physics">Nobel Prize in Physics</a> for theoretical work leading to the maser. Masers are used as timekeeping devices in <a href="/wiki/Atomic_clock" title="Atomic clock">atomic clocks</a>, and as extremely low-noise <a href="/wiki/Microwave" title="Microwave">microwave</a> amplifiers in <a href="/wiki/Radio_telescope" title="Radio telescope">radio telescopes</a> and deep-space <a href="/wiki/Spacecraft_communication" class="mw-redirect" title="Spacecraft communication">spacecraft communication</a> ground-stations. </p><figure typeof="mw:File/Thumb"><a href="/wiki/File:Charles_Townes_and_first_maser.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/92/Charles_Townes_and_first_maser.jpg/300px-Charles_Townes_and_first_maser.jpg" decoding="async" width="300" height="315" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/92/Charles_Townes_and_first_maser.jpg/450px-Charles_Townes_and_first_maser.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/92/Charles_Townes_and_first_maser.jpg/600px-Charles_Townes_and_first_maser.jpg 2x" data-file-width="975" data-file-height="1023"></a><figcaption>The first prototype <a href="/wiki/Ammonia" title="Ammonia">ammonia</a> maser in front of its inventor <a href="/wiki/Charles_H._Townes" title="Charles H. Townes">Charles H. Townes</a>. The ammonia nozzle is at left in the box, the four brass rods at center are the <a href="/wiki/Quadrupole_ion_trap" title="Quadrupole ion trap">quadrupole</a> state selector, and the resonant cavity is at right. The 24 GHz microwaves exit through the vertical <a href="/wiki/Waveguide" title="Waveguide">waveguide</a> Townes is adjusting. At bottom are the <a href="/wiki/Vacuum_pump" title="Vacuum pump">vacuum pumps</a>.</figcaption></figure> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Hydrogen_maser.gif" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c9/Hydrogen_maser.gif/330px-Hydrogen_maser.gif" decoding="async" width="260" height="340" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c9/Hydrogen_maser.gif/500px-Hydrogen_maser.gif 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c9/Hydrogen_maser.gif/520px-Hydrogen_maser.gif 2x" data-file-width="530" data-file-height="694"></a><figcaption>A hydrogen radio frequency discharge, the first element inside a <a href="#Hydrogen_maser">hydrogen maser</a> (see description below)</figcaption></figure> <p>Modern masers can be designed to generate electromagnetic waves at microwave <a href="/wiki/Frequencies" class="mw-redirect" title="Frequencies">frequencies</a> and <a href="/wiki/Radio_wave" title="Radio wave">radio</a> and <a href="/wiki/Infrared" title="Infrared">infrared</a> frequencies. For this reason, Townes suggested replacing "microwave" with "molecular" as the first word in the acronym "maser".<sup id="cite_ref-nobel_lecture_1-0" class="reference"><a href="#cite_note-nobel_lecture-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>The <i><a href="/wiki/Laser" title="Laser">laser</a></i> works by the same principle as the maser, but produces higher-frequency coherent radiation at <a href="/wiki/Visible_spectrum" title="Visible spectrum">visible</a> wavelengths. The maser was the precursor to the laser, inspiring theoretical work by Townes and <a href="/wiki/Arthur_Leonard_Schawlow" title="Arthur Leonard Schawlow">Arthur Leonard Schawlow</a> that led to the invention of the laser in 1960 by <a href="/wiki/Theodore_Maiman" title="Theodore Maiman">Theodore Maiman</a>. When the coherent optical oscillator was first imagined in 1957, it was originally called the "optical maser". This was ultimately changed to <em>laser</em>, for "light amplification by stimulated emission of radiation". <a href="/wiki/Gordon_Gould" title="Gordon Gould">Gordon Gould</a> is credited with creating this acronym in 1957. </p> <div id="toc" class="toc" role="navigation" aria-labelledby="mw-toc-heading"><input type="checkbox" role="button" id="toctogglecheckbox" class="toctogglecheckbox" style="display:none"><div class="toctitle" lang="en" dir="ltr"><h2 id="mw-toc-heading">Contents</h2><span class="toctogglespan"><label class="toctogglelabel" for="toctogglecheckbox"></label></span></div> <ul> <li class="toclevel-1 tocsection-1"><a href="#History"><span class="tocnumber">1</span> <span class="toctext">History</span></a></li> <li class="toclevel-1 tocsection-2"><a href="#Technology"><span class="tocnumber">2</span> <span class="toctext">Technology</span></a> <ul> <li class="toclevel-2 tocsection-3"><a href="#Some_common_types"><span class="tocnumber">2.1</span> <span class="toctext">Some common types</span></a></li> <li class="toclevel-2 tocsection-4"><a href="#21st-century_developments"><span class="tocnumber">2.2</span> <span class="toctext">21st-century developments</span></a></li> </ul> </li> <li class="toclevel-1 tocsection-5"><a href="#Uses"><span class="tocnumber">3</span> <span class="toctext">Uses</span></a> <ul> <li class="toclevel-2 tocsection-6"><a href="#Hydrogen_maser"><span class="tocnumber">3.1</span> <span class="toctext">Hydrogen maser</span></a></li> </ul> </li> <li class="toclevel-1 tocsection-7"><a href="#Astrophysical_masers"><span class="tocnumber">4</span> <span class="toctext">Astrophysical masers</span></a></li> <li class="toclevel-1 tocsection-8"><a href="#Terminology"><span class="tocnumber">5</span> <span class="toctext">Terminology</span></a></li> <li class="toclevel-1 tocsection-9"><a href="#See_also"><span class="tocnumber">6</span> <span class="toctext">See also</span></a></li> <li class="toclevel-1 tocsection-10"><a href="#References"><span class="tocnumber">7</span> <span class="toctext">References</span></a></li> <li class="toclevel-1 tocsection-11"><a href="#Further_reading"><span class="tocnumber">8</span> <span class="toctext">Further reading</span></a></li> <li class="toclevel-1 tocsection-12"><a href="#External_links"><span class="tocnumber">9</span> <span class="toctext">External links</span></a></li> </ul> </div> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(1)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="History">History</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=1" title="Edit section: History" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-1 collapsible-block" id="mf-section-1"> <p>The theoretical principles governing the operation of a maser were first described by <a href="/wiki/Joseph_Weber" title="Joseph Weber">Joseph Weber</a> of the <a href="/wiki/University_of_Maryland,_College_Park" title="University of Maryland, College Park">University of Maryland, College Park</a> at the Electron Tube Research Conference in June 1952 in <a href="/wiki/Ottawa" title="Ottawa">Ottawa</a>,<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> with a summary published in the June 1953 Transactions of the Institute of Radio Engineers Professional Group on Electron Devices,<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> and simultaneously by <a href="/wiki/Nikolay_Basov" title="Nikolay Basov">Nikolay Basov</a> and <a href="/wiki/Alexander_Prokhorov" title="Alexander Prokhorov">Alexander Prokhorov</a> from <a href="/wiki/Lebedev_Physical_Institute" title="Lebedev Physical Institute">Lebedev Institute of Physics</a>, at an <i>All-Union Conference on Radio-Spectroscopy</i> held by the <a href="/wiki/USSR_Academy_of_Sciences" class="mw-redirect" title="USSR Academy of Sciences">USSR Academy of Sciences</a> in May 1952, published in October 1954. </p><p>Independently, <a href="/wiki/Charles_H._Townes" title="Charles H. Townes">Charles Hard Townes</a>, <a href="/wiki/James_P._Gordon" title="James P. Gordon">James P. Gordon</a>, and H. J. Zeiger built the first ammonia maser at <a href="/wiki/Columbia_University" title="Columbia University">Columbia University</a> in 1953. This device used stimulated emission in a stream of energized <a href="/wiki/Ammonia" title="Ammonia">ammonia</a> molecules to produce amplification of microwaves at a frequency of about 24.0 <a href="/wiki/Hertz" title="Hertz">gigahertz</a>.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> Townes later worked with <a href="/wiki/Arthur_Leonard_Schawlow" title="Arthur Leonard Schawlow">Arthur L. Schawlow</a> to describe the principle of the <i>optical maser</i>, or <i>laser</i>,<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> of which <a href="/wiki/Theodore_Harold_Maiman" class="mw-redirect" title="Theodore Harold Maiman">Theodore H. Maiman</a> created the first working model in 1960. </p><p>For their research in the field of stimulated emission, Townes, Basov and Prokhorov were awarded the <a href="/wiki/Nobel_Prize_in_Physics" title="Nobel Prize in Physics">Nobel Prize in Physics</a> in 1964.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(2)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Technology">Technology</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=2" title="Edit section: Technology" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-2 collapsible-block" id="mf-section-2"> <p>The maser is based on the principle of stimulated emission proposed by <a href="/wiki/Albert_Einstein" title="Albert Einstein">Albert Einstein</a> in 1917. When atoms have been induced into an excited energy state, they can amplify radiation at a frequency particular to the element or molecule used as the masing medium (similar to what occurs in the lasing medium in a laser). </p><p>By putting such an amplifying medium in a <a href="/wiki/Resonant_cavity" class="mw-redirect" title="Resonant cavity">resonant cavity</a>, feedback is created that can produce <a href="/wiki/Coherence_(physics)" title="Coherence (physics)">coherent radiation</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Some_common_types">Some common types</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=3" title="Edit section: Some common types" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <ul><li>Atomic beam masers <ul><li>Ammonia maser</li> <li>Free electron maser</li> <li><a href="/wiki/Hydrogen_maser" title="Hydrogen maser">Hydrogen maser</a></li></ul></li> <li>Gas masers <ul><li>Rubidium maser</li></ul></li> <li>Liquid-dye and chemical laser</li> <li>Solid state masers <ul><li>Ruby maser</li> <li><a href="/wiki/Whispering-gallery_wave" title="Whispering-gallery wave">Whispering-gallery modes</a> iron-sapphire maser</li></ul></li> <li>Dual noble gas maser (The dual <a href="/wiki/Noble_gas" title="Noble gas">noble gas</a> of a masing medium which is <a href="/wiki/Nonpolar" class="mw-redirect" title="Nonpolar">nonpolar</a>.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup>)</li></ul> <div class="mw-heading mw-heading3"><h3 id="21st-century_developments">21st-century developments</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=4" title="Edit section: 21st-century developments" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <p>In 2012, a research team from the <a href="/wiki/National_Physical_Laboratory_(United_Kingdom)" title="National Physical Laboratory (United Kingdom)">National Physical Laboratory</a> and <a href="/wiki/Imperial_College_London" title="Imperial College London">Imperial College London</a> developed a <a href="/wiki/Solid-state_physics" title="Solid-state physics">solid-state</a> maser that operated at room temperature by using optically pumped, <a href="/wiki/Pentacene" title="Pentacene">pentacene</a>-doped <a href="/wiki/P-Terphenyl" class="mw-redirect" title="P-Terphenyl">p-Terphenyl</a> as the amplifier medium.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> It produced pulses of maser emission lasting for a few hundred microseconds. </p><p>In 2018, a research team from <a href="/wiki/Imperial_College_London" title="Imperial College London">Imperial College London</a> and <a href="/wiki/University_College_London" title="University College London">University College London</a> demonstrated continuous-wave maser oscillation using <a href="/wiki/Synthetic_diamond" title="Synthetic diamond">synthetic diamonds</a> containing <a href="/wiki/Nitrogen-vacancy_center" title="Nitrogen-vacancy center">nitrogen-vacancy</a> defects.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(3)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Uses">Uses</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=5" title="Edit section: Uses" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-3 collapsible-block" id="mf-section-3"> <p>Masers serve as high precision <a href="/wiki/Frequency_reference" class="mw-redirect" title="Frequency reference">frequency references</a>. These "atomic frequency standards" are one of the many forms of <a href="/wiki/Atomic_clock" title="Atomic clock">atomic clocks</a>. Masers were also used as <a href="/wiki/Electronic_amplifier" class="mw-redirect" title="Electronic amplifier">low-noise microwave amplifiers</a> in <a href="/wiki/Radio_telescope" title="Radio telescope">radio telescopes</a>, though these have largely been replaced by amplifiers based on <a href="/wiki/Field_effect_transistor" class="mw-redirect" title="Field effect transistor">FETs</a>.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </p><p>During the early 1960s, the <a href="/wiki/Jet_Propulsion_Laboratory" title="Jet Propulsion Laboratory">Jet Propulsion Laboratory</a> developed a maser to provide ultra-low-noise amplification of <a href="/wiki/S-band" class="mw-redirect" title="S-band">S-band</a> microwave signals received from deep space probes.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> This maser used deeply refrigerated helium to chill the amplifier down to a temperature of 4 <a href="/wiki/Kelvin" title="Kelvin">kelvin</a>. Amplification was achieved by exciting a ruby comb with a 12.0 gigahertz <a href="/wiki/Klystron" title="Klystron">klystron</a>. In the early years, it took days to chill and remove the impurities from the hydrogen lines. </p><p>Refrigeration was a two-stage process, with a large Linde unit on the ground, and a crosshead compressor within the antenna. The final injection was at 21 MPa (3,000 psi) through a 150 μm (0.006 in) micrometer-adjustable entry to the chamber. The whole system <a href="/wiki/Noise_temperature" title="Noise temperature">noise temperature</a> looking at cold sky (2.7 <a href="/wiki/Kelvin" title="Kelvin">kelvin</a> in the microwave band) was 17 kelvin. This gave such a low noise figure that the <a href="/wiki/Mariner_IV" class="mw-redirect" title="Mariner IV">Mariner IV</a> <a href="/wiki/Space_probe" class="mw-redirect" title="Space probe">space probe</a> could send still pictures from <a href="/wiki/Mars" title="Mars">Mars</a> back to the <a href="/wiki/Earth" title="Earth">Earth</a>, even though the output power of its <a href="/wiki/Radio_transmitter" class="mw-redirect" title="Radio transmitter">radio transmitter</a> was only 15 <a href="/wiki/Watt" title="Watt">watts</a>, and hence the total signal power received was only −169 <a href="/wiki/Decibel" title="Decibel">decibels</a> with respect to a <a href="/wiki/Milliwatt" class="mw-redirect" title="Milliwatt">milliwatt</a> (dBm). </p> <div class="mw-heading mw-heading3"><h3 id="Hydrogen_maser">Hydrogen maser</h3><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=6" title="Edit section: Hydrogen maser" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Hydrogen_maser" title="Hydrogen maser">Hydrogen maser</a></div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Hmaser.svg" class="mw-file-description"><noscript><img src="//upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Hmaser.svg/200px-Hmaser.svg.png" decoding="async" width="200" height="375" class="mw-file-element" data-file-width="200" data-file-height="375"></noscript><span class="lazy-image-placeholder" style="width: 200px;height: 375px;" data-mw-src="//upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Hmaser.svg/200px-Hmaser.svg.png" data-width="200" data-height="375" data-mw-srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Hmaser.svg/300px-Hmaser.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Hmaser.svg/400px-Hmaser.svg.png 2x" data-class="mw-file-element"> </span></a><figcaption>A hydrogen maser.</figcaption></figure> <p>The hydrogen maser is used as an <a href="/wiki/Atomic_clock" title="Atomic clock">atomic frequency standard</a>. Together with other kinds of atomic clocks, these help make up the <a href="/wiki/International_Atomic_Time" title="International Atomic Time">International Atomic Time</a> standard ("Temps Atomique International" or "TAI" in French). This is the international time scale coordinated by the <a href="/wiki/International_Bureau_of_Weights_and_Measures" title="International Bureau of Weights and Measures">International Bureau of Weights and Measures</a>. <a href="/wiki/Norman_Ramsey" class="mw-redirect" title="Norman Ramsey">Norman Ramsey</a> and his colleagues first conceived of the maser as a timing standard. More recent masers are practically identical to their original design. Maser oscillations rely on the stimulated emission between two <a href="/wiki/Hyperfine_structure" title="Hyperfine structure">hyperfine energy levels</a> of atomic <a href="/wiki/Hydrogen" title="Hydrogen">hydrogen</a>. </p><p>Here is a brief description of how they work: </p> <ul><li>First, a beam of atomic hydrogen is produced. This is done by submitting the gas at low pressure to a high-frequency <a href="/wiki/Radio_wave" title="Radio wave">radio wave</a> discharge (see the picture on this page).</li> <li>The next step is "state selection"—in order to get some stimulated emission, it is necessary to create a <a href="/wiki/Population_inversion" title="Population inversion">population inversion</a> of the atoms. This is done in a way that is very similar to the <a href="/wiki/Stern%E2%80%93Gerlach_experiment" title="Stern–Gerlach experiment">Stern–Gerlach experiment</a>. After passing through an aperture and a magnetic field, many of the atoms in the beam are left in the upper energy level of the lasing transition. From this state, the atoms can decay to the lower state and emit some microwave radiation.</li> <li>A high <a href="/wiki/Q_factor" title="Q factor">Q factor</a> (quality factor) <a href="/wiki/Microwave_cavity" title="Microwave cavity">microwave cavity</a> confines the microwaves and reinjects them repeatedly into the atom beam. The stimulated emission amplifies the microwaves on each pass through the beam. This combination of <a href="/wiki/Amplifier" title="Amplifier">amplification</a> and <a href="/wiki/Feedback" title="Feedback">feedback</a> is what defines all <a href="/wiki/Oscillator" class="mw-redirect" title="Oscillator">oscillators</a>. The <a href="/wiki/Resonant_frequency" class="mw-redirect" title="Resonant frequency">resonant frequency</a> of the microwave cavity is tuned to the frequency of the hyperfine <a href="/wiki/Energy_level#Energy_level_transitions" title="Energy level">energy transition</a> of hydrogen: 1,420,405,752 <a href="/wiki/Hertz" title="Hertz">hertz</a>.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup></li> <li>A small fraction of the signal in the microwave cavity is coupled into a coaxial cable and then sent to a coherent <a href="/wiki/Radio_receiver" title="Radio receiver">radio receiver</a>.</li> <li>The microwave signal coming out of the maser is very weak, a few <a href="/wiki/Picowatt" class="mw-redirect" title="Picowatt">picowatts</a>. The frequency of the signal is fixed and <i>extremely</i> stable. The coherent receiver is used to amplify the signal and change the frequency. This is done using a series of <a href="/wiki/Phase-locked_loop" title="Phase-locked loop">phase-locked loops</a> and a high performance <a href="/wiki/Quartz_oscillator" class="mw-redirect" title="Quartz oscillator">quartz oscillator</a>.</li></ul> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(4)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Astrophysical_masers">Astrophysical masers</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=7" title="Edit section: Astrophysical masers" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-4 collapsible-block" id="mf-section-4"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Astrophysical_maser" title="Astrophysical maser">Astrophysical maser</a></div> <p>Maser-like stimulated emission has also been observed in nature from <a href="/wiki/Interstellar_space" class="mw-redirect" title="Interstellar space">interstellar space</a>, and it is frequently called "superradiant emission" to distinguish it from laboratory masers. Such emission is observed from molecules such as water (H<sub>2</sub>O), <a href="/wiki/Hydroxyl_radical" title="Hydroxyl radical">hydroxyl radicals</a> (<a href="/wiki/OH_masers" class="mw-redirect" title="OH masers">•OH</a>), <a href="/wiki/Methanol" title="Methanol">methanol</a> (CH<sub>3</sub>OH), <a href="/wiki/Formaldehyde" title="Formaldehyde">formaldehyde</a> (HCHO), <a href="/wiki/Silicon_monoxide" title="Silicon monoxide">silicon monoxide</a> (SiO), and <a href="/wiki/Carbodiimide" title="Carbodiimide">carbodiimide</a> (HNCNH).<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> Water molecules in <a href="/wiki/Star" title="Star">star</a>-forming regions can undergo a <a href="/wiki/Population_inversion" title="Population inversion">population inversion</a> and emit radiation at about 22.0 <a href="/wiki/GHz" class="mw-redirect" title="GHz">GHz</a>, creating the brightest <a href="/wiki/Electromagnetic_spectrum" title="Electromagnetic spectrum">spectral line</a> in the radio universe. Some water masers also emit radiation from a <a href="/wiki/Quantum_rotor_model" title="Quantum rotor model">rotational transition</a> at a <a href="/wiki/Frequency" title="Frequency">frequency</a> of 96 GHz.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p><p>Extremely powerful masers, associated with <a href="/wiki/Active_galactic_nuclei" class="mw-redirect" title="Active galactic nuclei">active galactic nuclei</a>, are known as <a href="/wiki/Megamaser" title="Megamaser">megamasers</a> and are up to a million times more powerful than stellar masers. </p> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(5)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Terminology">Terminology</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=8" title="Edit section: Terminology" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-5 collapsible-block" id="mf-section-5"> <p>The meaning of the term <i>maser</i> has changed slightly since its introduction. Initially the acronym was universally given as "microwave amplification by stimulated emission of radiation", which described devices which emitted in the microwave region of the <a href="/wiki/Electromagnetic_spectrum" title="Electromagnetic spectrum">electromagnetic spectrum</a>. </p><p>The principle and concept of stimulated emission has since been extended to more devices and frequencies. Thus, the original acronym is sometimes modified, as suggested by Charles H. Townes,<sup id="cite_ref-nobel_lecture_1-1" class="reference"><a href="#cite_note-nobel_lecture-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> to "<i>molecular</i> amplification by stimulated emission of radiation." Some have asserted that Townes's efforts to extend the acronym in this way were primarily motivated by the desire to increase the importance of his invention, and his reputation in the scientific community.<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> </p><p>When the laser was developed, Townes and <a href="/wiki/Arthur_Schawlow" class="mw-redirect" title="Arthur Schawlow">Schawlow</a> and their colleagues at Bell Labs pushed the use of the term <i>optical maser</i>, but this was largely abandoned in favor of <i>laser</i>, coined by their rival Gordon Gould.<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> In modern usage, devices that emit in the <a href="/wiki/X-ray" title="X-ray">X-ray</a> through <a href="/wiki/Infrared" title="Infrared">infrared</a> portions of the spectrum are typically called <a href="/wiki/Laser" title="Laser">lasers</a>, and devices that emit in the microwave region and below are commonly called <i>masers</i>, regardless of whether they emit microwaves or other frequencies. </p><p>Gould originally proposed distinct names for devices that emit in each portion of the spectrum, including <i>grasers</i> (<a href="/wiki/Gamma_ray" title="Gamma ray">gamma ray</a> lasers), <i>xasers</i> (x-ray lasers), <i>uvasers</i> (<a href="/wiki/Ultraviolet" title="Ultraviolet">ultraviolet</a> lasers), <i>lasers</i> (<a href="/wiki/Visible_light" class="mw-redirect" title="Visible light">visible</a> lasers), <i>irasers</i> (<a href="/wiki/Infrared" title="Infrared">infrared</a> lasers), <i>masers</i> (microwave masers), and <i>rasers</i> (<a href="/wiki/Radio_frequency" title="Radio frequency">RF</a> masers). Most of these terms never caught on, however, and all have now become (apart from in science fiction) obsolete except for <i>maser</i> and <i>laser</i>.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (April 2022)">citation needed</span></a></i>]</sup> </p> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(6)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="See_also">See also</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=9" title="Edit section: See also" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-6 collapsible-block" id="mf-section-6"> <ul><li><a href="/wiki/List_of_laser_types" title="List of laser types">List of laser types</a></li> <li><a href="/wiki/X-ray_laser" title="X-ray laser">X-ray laser</a></li> <li><a href="/wiki/Gamma-ray_laser" title="Gamma-ray laser">Gamma-ray laser</a> (<a href="/wiki/Graser" class="mw-redirect" title="Graser">graser</a>)</li> <li><a href="/wiki/Sonic_laser" class="mw-redirect" title="Sonic laser">Sonic laser</a> (<a href="/wiki/Sonic_laser" class="mw-redirect" title="Sonic laser">saser</a>)</li> <li><a href="/wiki/Spaser" title="Spaser">Spaser</a></li></ul> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(7)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="References">References</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=10" title="Edit section: References" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-7 collapsible-block" id="mf-section-7"> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-nobel_lecture-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-nobel_lecture_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-nobel_lecture_1-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFTownes1964" class="citation web cs1"><a href="/wiki/Charles_H._Townes" title="Charles H. Townes">Townes, Charles H.</a> (1964-12-11). <a rel="nofollow" class="external text" href="https://www.nobelprize.org/uploads/2018/06/townes-lecture.pdf">"Production of coherent radiation by atoms and molecules - Nobel Lecture"</a> <span class="cs1-format">(PDF)</span>. <i>The Nobel Prize</i>. p. 63. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20200827171449/https://www.nobelprize.org/uploads/2018/06/townes-lecture.pdf">Archived</a> <span class="cs1-format">(pdf)</span> from the original on 2020-08-27<span class="reference-accessdate">. Retrieved <span class="nowrap">2020-08-27</span></span>. <q>We called this general type of system the maser, an acronym for microwave amplification by stimulated emission of radiation. The idea has been successfully extended to such a variety of devices and frequencies that it is probably well to generalize the name - perhaps to mean molecular amplification by stimulated emission of radiation.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Nobel+Prize&rft.atitle=Production+of+coherent+radiation+by+atoms+and+molecules+-+Nobel+Lecture&rft.pages=63&rft.date=1964-12-11&rft.aulast=Townes&rft.aufirst=Charles+H.&rft_id=https%3A%2F%2Fwww.nobelprize.org%2Fuploads%2F2018%2F06%2Ftownes-lecture.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.aip.org/history-programs/niels-bohr-library/oral-histories/4941">American Institute of Physics Oral History Interview with Weber</a></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMario_Bertolotti2004" class="citation book cs1">Mario Bertolotti (2004). <i>The History of the Laser</i>. CRC Press. p. 180. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1420033403" title="Special:BookSources/978-1420033403"><bdi>978-1420033403</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+History+of+the+Laser&rft.pages=180&rft.pub=CRC+Press&rft.date=2004&rft.isbn=978-1420033403&rft.au=Mario+Bertolotti&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGordonZeigerTownes1955" class="citation journal cs1">Gordon, J. P.; Zeiger, H. J.; Townes, C. H. (1955). <a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRev.99.1264">"The Maser—New Type of Microwave Amplifier, Frequency Standard, and Spectrometer"</a>. <i>Phys. Rev</i>. <b>99</b> (4): 1264. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1955PhRv...99.1264G">1955PhRv...99.1264G</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRev.99.1264">10.1103/PhysRev.99.1264</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Phys.+Rev.&rft.atitle=The+Maser%E2%80%94New+Type+of+Microwave+Amplifier%2C+Frequency+Standard%2C+and+Spectrometer&rft.volume=99&rft.issue=4&rft.pages=1264&rft.date=1955&rft_id=info%3Adoi%2F10.1103%2FPhysRev.99.1264&rft_id=info%3Abibcode%2F1955PhRv...99.1264G&rft.aulast=Gordon&rft.aufirst=J.+P.&rft.au=Zeiger%2C+H.+J.&rft.au=Townes%2C+C.+H.&rft_id=https%3A%2F%2Fdoi.org%2F10.1103%252FPhysRev.99.1264&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSchawlowTownes1958" class="citation journal cs1">Schawlow, A.L.; Townes, C.H. 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Retrieved <span class="nowrap">23 August</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=%27Maser%27+source+of+microwave+beams+comes+out+of+the+cold&rft.date=2012-08-16&rft.aulast=Palmer&rft.aufirst=Jason&rft_id=https%3A%2F%2Fwww.bbc.co.uk%2Fnews%2Fscience-environment-19281566&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.nature.com/news/microwave-laser-fulfills-60-years-of-promise-1.11199">Microwave Laser Fulfills 60 Years of Promise</a></span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLiu2018" class="citation journal cs1">Liu, Ren-Bao (March 2018). <a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fd41586-018-03215-3">"A diamond age of masers"</a>. <i>Nature</i>. <b>555</b> (7697): <span class="nowrap">447–</span>449. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2018Natur.555..447L">2018Natur.555..447L</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fd41586-018-03215-3">10.1038/d41586-018-03215-3</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/29565370">29565370</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Nature&rft.atitle=A+diamond+age+of+masers&rft.volume=555&rft.issue=7697&rft.pages=%3Cspan+class%3D%22nowrap%22%3E447-%3C%2Fspan%3E449&rft.date=2018-03&rft_id=info%3Apmid%2F29565370&rft_id=info%3Adoi%2F10.1038%2Fd41586-018-03215-3&rft_id=info%3Abibcode%2F2018Natur.555..447L&rft.aulast=Liu&rft.aufirst=Ren-Bao&rft_id=https%3A%2F%2Fdoi.org%2F10.1038%252Fd41586-018-03215-3&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://phys.org/news/2018-03-scientists-diamond-world-room-temperature-solid-state.html">Scientists use diamond in world's first continuous room-temperature solid-state maser</a>, phys.org</span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://science.nrao.edu/facilities/cdl/low-noise-amplifiers">"Low Noise Amplifiers – Pushing the limits of low noise"</a>. National Radio Astronomy Observatory (NRAO).</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Low+Noise+Amplifiers+%E2%80%93+Pushing+the+limits+of+low+noise&rft.pub=National+Radio+Astronomy+Observatory+%28NRAO%29&rft_id=https%3A%2F%2Fscience.nrao.edu%2Ffacilities%2Fcdl%2Flow-noise-amplifiers&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMacgregor_S._Reid2008" class="citation web cs1">Macgregor S. Reid, ed. (2008). <a rel="nofollow" class="external text" href="https://descanso.jpl.nasa.gov/monograph/series10/Reid_DESCANSO_sml-110804.pdf">"Low-Noise Systems in the Deep Space Network"</a> <span class="cs1-format">(PDF)</span>. JPL.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Low-Noise+Systems+in+the+Deep+Space+Network&rft.pub=JPL&rft.date=2008&rft_id=https%3A%2F%2Fdescanso.jpl.nasa.gov%2Fmonograph%2Fseries10%2FReid_DESCANSO_sml-110804.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation journal cs1"><a rel="nofollow" class="external text" href="https://www.nist.gov/pml/time-and-frequency-division/popular-links/time-frequency-z/time-and-frequency-z-h">"Time and Frequency From A to Z: H"</a>. <i>NIST</i>. 12 May 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=NIST&rft.atitle=Time+and+Frequency+From+A+to+Z%3A+H&rft.date=2010-05-12&rft_id=https%3A%2F%2Fwww.nist.gov%2Fpml%2Ftime-and-frequency-division%2Fpopular-links%2Ftime-frequency-z%2Ftime-and-frequency-z-h&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMcGuireLoomisCharnessCorby2012" class="citation journal cs1">McGuire, Brett A.; Loomis, Ryan A.; Charness, Cameron M.; Corby, Joanna F.; Blake, Geoffrey A.; Hollis, Jan M.; Lovas, Frank J.; Jewell, Philip R.; Remijan, Anthony J. (2012-10-20). <a rel="nofollow" class="external text" href="https://iopscience.iop.org/article/10.1088/2041-8205/758/2/L33">"Interstellar Carbodiimide (HNCNH): A New Astronomical Detection from the GBT Primos Survey Via Maser Emission Features"</a>. <i>The Astrophysical Journal</i>. <b>758</b> (2): L33. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://arxiv.org/abs/1209.1590">1209.1590</a></span>. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2012ApJ...758L..33M">2012ApJ...758L..33M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1088%2F2041-8205%2F758%2F2%2FL33">10.1088/2041-8205/758/2/L33</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/2041-8205">2041-8205</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:26146516">26146516</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Astrophysical+Journal&rft.atitle=Interstellar+Carbodiimide+%28HNCNH%29%3A+A+New+Astronomical+Detection+from+the+GBT+Primos+Survey+Via+Maser+Emission+Features&rft.volume=758&rft.issue=2&rft.pages=L33&rft.date=2012-10-20&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A26146516%23id-name%3DS2CID&rft_id=info%3Abibcode%2F2012ApJ...758L..33M&rft_id=info%3Aarxiv%2F1209.1590&rft.issn=2041-8205&rft_id=info%3Adoi%2F10.1088%2F2041-8205%2F758%2F2%2FL33&rft.aulast=McGuire&rft.aufirst=Brett+A.&rft.au=Loomis%2C+Ryan+A.&rft.au=Charness%2C+Cameron+M.&rft.au=Corby%2C+Joanna+F.&rft.au=Blake%2C+Geoffrey+A.&rft.au=Hollis%2C+Jan+M.&rft.au=Lovas%2C+Frank+J.&rft.au=Jewell%2C+Philip+R.&rft.au=Remijan%2C+Anthony+J.&rft_id=https%3A%2F%2Fiopscience.iop.org%2Farticle%2F10.1088%2F2041-8205%2F758%2F2%2FL33&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNeufeldMelnick1991" class="citation journal cs1">Neufeld, David A.; Melnick, Gary J. (1991). "Excitation of Millimeter and Submillimeter Water Masers in Warm Astrophysical Gas". <i>Atoms, Ions and Molecules: New Results in Spectral Line Astrophysics, ASP Conference Series (ASP: San Francisco)</i>. <b>16</b>: 163. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1991ASPC...16..163N">1991ASPC...16..163N</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Atoms%2C+Ions+and+Molecules%3A+New+Results+in+Spectral+Line+Astrophysics%2C+ASP+Conference+Series+%28ASP%3A+San+Francisco%29&rft.atitle=Excitation+of+Millimeter+and+Submillimeter+Water+Masers+in+Warm+Astrophysical+Gas&rft.volume=16&rft.pages=163&rft.date=1991&rft_id=info%3Abibcode%2F1991ASPC...16..163N&rft.aulast=Neufeld&rft.aufirst=David+A.&rft.au=Melnick%2C+Gary+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTennyson2013" class="citation journal cs1">Tennyson, Jonathan; et al. (March 2013). <a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.jqsrt.2012.10.002">"IUPAC critical evaluation of the rotational–vibrational spectra of water vapor, Part III: Energy levels and transition wavenumbers for H<sub>2</sub><sup>16</sup>O"</a>. <i>Journal of Quantitative Spectroscopy and Radiative Transfer</i>. <b>117</b>: <span class="nowrap">29–</span>58. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2013JQSRT.117...29T">2013JQSRT.117...29T</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.jqsrt.2012.10.002">10.1016/j.jqsrt.2012.10.002</a></span>. <a href="/wiki/Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://hdl.handle.net/10831%2F91303">10831/91303</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Quantitative+Spectroscopy+and+Radiative+Transfer&rft.atitle=IUPAC+critical+evaluation+of+the+rotational%E2%80%93vibrational+spectra+of+water+vapor%2C+Part+III%3A+Energy+levels+and+transition+wavenumbers+for+H%3Csub%3E2%3C%2Fsub%3E%3Csup%3E16%3C%2Fsup%3EO&rft.volume=117&rft.pages=%3Cspan+class%3D%22nowrap%22%3E29-%3C%2Fspan%3E58&rft.date=2013-03&rft_id=info%3Ahdl%2F10831%2F91303&rft_id=info%3Adoi%2F10.1016%2Fj.jqsrt.2012.10.002&rft_id=info%3Abibcode%2F2013JQSRT.117...29T&rft.aulast=Tennyson&rft.aufirst=Jonathan&rft_id=https%3A%2F%2Fdoi.org%2F10.1016%252Fj.jqsrt.2012.10.002&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTaylor2000" class="citation book cs1">Taylor, Nick (2000). <i>LASER: The inventor, the Nobel laureate, and the thirty-year patent war</i>. New York: Simon & Schuster. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-684-83515-0" title="Special:BookSources/978-0-684-83515-0"><bdi>978-0-684-83515-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=LASER%3A+The+inventor%2C+the+Nobel+laureate%2C+and+the+thirty-year+patent+war&rft.place=New+York&rft.pub=Simon+%26+Schuster&rft.date=2000&rft.isbn=978-0-684-83515-0&rft.aulast=Taylor&rft.aufirst=Nick&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> <li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFTaylor2000" class="citation book cs1">Taylor, Nick (2000). <i>LASER: The inventor, the Nobel laureate, and the thirty-year patent war</i>. New York: Simon & Schuster. pp. <span class="nowrap">66–</span>70. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-684-83515-0" title="Special:BookSources/978-0-684-83515-0"><bdi>978-0-684-83515-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=LASER%3A+The+inventor%2C+the+Nobel+laureate%2C+and+the+thirty-year+patent+war&rft.place=New+York&rft.pages=%3Cspan+class%3D%22nowrap%22%3E66-%3C%2Fspan%3E70&rft.pub=Simon+%26+Schuster&rft.date=2000&rft.isbn=978-0-684-83515-0&rft.aulast=Taylor&rft.aufirst=Nick&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></span> </li> </ol></div></div> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(8)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=11" title="Edit section: Further reading" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-8 collapsible-block" id="mf-section-8"> <ul><li>J.R. Singer, <i>Masers</i>, John Whiley and Sons Inc., 1959.</li> <li>J. Vanier, C. Audoin, <i>The Quantum Physics of Atomic Frequency Standards</i>, Adam Hilger, Bristol, 1989.</li></ul> </section><div class="mw-heading mw-heading2 section-heading" onclick="mfTempOpenSection(9)"><span class="indicator mf-icon mf-icon-expand mf-icon--small"></span><h2 id="External_links">External links</h2><span class="mw-editsection"> <a role="button" href="/w/index.php?title=Maser&action=edit&section=12" title="Edit section: External links" class="cdx-button cdx-button--size-large cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--icon-only cdx-button--weight-quiet "> <span class="minerva-icon minerva-icon--edit"></span> <span>edit</span> </a> </span> </div><section class="mf-section-9 collapsible-block" id="mf-section-9"> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1237033735">@media print{body.ns-0 .mw-parser-output .sistersitebox{display:none!important}}@media screen{html.skin-theme-clientpref-night .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sistersitebox img[src*="Wiktionary-logo-en-v2.svg"]{background-color:white}}</style><div class="side-box side-box-right plainlinks sistersitebox"><style data-mw-deduplicate="TemplateStyles:r1126788409">.mw-parser-output .plainlist ol,.mw-parser-output .plainlist ul{line-height:inherit;list-style:none;margin:0;padding:0}.mw-parser-output .plainlist ol li,.mw-parser-output .plainlist ul li{margin-bottom:0}</style> <div class="side-box-flex"> <div class="side-box-image"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Commons-logo.svg" class="mw-file-description"><noscript><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/40px-Commons-logo.svg.png" decoding="async" width="30" height="40" class="mw-file-element" data-file-width="1024" data-file-height="1376"></noscript><span class="lazy-image-placeholder" style="width: 30px;height: 40px;" data-mw-src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/40px-Commons-logo.svg.png" data-alt="" data-width="30" data-height="40" data-mw-srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/60px-Commons-logo.svg.png 1.5x" data-class="mw-file-element"> </span></a></span></div> <div class="side-box-text plainlist">Wikimedia Commons has media related to <span style="font-weight: bold; font-style: italic;"><a href="https://commons.wikimedia.org/wiki/Category:Masers" class="extiw" title="commons:Category:Masers">Masers</a></span>.</div></div> </div> <ul><li><a rel="nofollow" class="external text" href="https://feynmanlectures.caltech.edu/III_09.html">The Feynman Lectures on Physics Vol. III Ch. 9: The Ammonia Maser</a></li> <li><a rel="nofollow" class="external text" href="https://arxiv.org/find/grp_physics/1/ti:+maser/0/1/0/all/0/1?per_page=100;">arXiv.org search for "maser"</a></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20061010151459/http://www.cfa.harvard.edu/hmc/">"The Hydrogen Maser Clock Project"</a>. Harvard-Smithsonian Center for Astrophysics. Archived from <a rel="nofollow" class="external text" href="http://cfa-www.harvard.edu/hmc/">the original</a> on 2006-10-10.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Hydrogen+Maser+Clock+Project&rft.pub=Harvard-Smithsonian+Center+for+Astrophysics&rft_id=http%3A%2F%2Fcfa-www.harvard.edu%2Fhmc%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AMaser" class="Z3988"></span></li> <li><a rel="nofollow" class="external text" href="http://www.aip.org/history/exhibits/laser">Bright Idea: The First Lasers</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20140424130338/http://www.aip.org/history/exhibits/laser/">Archived</a> 2014-04-24 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a></li> <li><a rel="nofollow" class="external text" href="https://physics.aps.org/story/v15/st4">Invention of the Maser and Laser</a>, <a href="/wiki/American_Physical_Society" title="American Physical Society">American Physical Society</a></li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20061017080654/http://www.bell-labs.com/about/history/laser/">Shawlow and Townes Invent the Laser</a>, <a href="/wiki/Bell_Labs" title="Bell Labs">Bell Labs</a></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul 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data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Maser&oldid=1277192825">https://en.wikipedia.org/w/index.php?title=Maser&oldid=1277192825</a>"</div></div> </div> <div class="post-content" id="page-secondary-actions"> </div> </main> <footer class="mw-footer minerva-footer" role="contentinfo"> <a class="last-modified-bar" href="/w/index.php?title=Maser&action=history"> <div class="post-content last-modified-bar__content"> <span class="minerva-icon minerva-icon-size-medium minerva-icon--modified-history"></span> <span class="last-modified-bar__text modified-enhancement" data-user-name="120.22.58.216" data-user-gender="unknown" data-timestamp="1740293821"> <span>Last edited on 23 February 2025, at 06:57</span> </span> <span class="minerva-icon minerva-icon-size-small minerva-icon--expand"></span> </div> </a> <div class="post-content footer-content"> <div id='mw-data-after-content'> <div class="read-more-container"></div> </div> <div id="p-lang"> <h4>Languages</h4> <section> <ul id="p-variants" class="minerva-languages"></ul> <ul class="minerva-languages"><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%85%D9%8A%D8%B2%D8%B1" title="ميزر – Arabic" lang="ar" hreflang="ar" data-title="ميزر" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-an mw-list-item"><a href="https://an.wikipedia.org/wiki/Maser" title="Maser – Aragonese" lang="an" hreflang="an" data-title="Maser" data-language-autonym="Aragonés" data-language-local-name="Aragonese" class="interlanguage-link-target"><span>Aragonés</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Mazer" title="Mazer – Azerbaijani" lang="az" hreflang="az" data-title="Mazer" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%9C%D0%B0%D0%B7%D0%B5%D1%80" title="Мазер – Belarusian" lang="be" hreflang="be" data-title="Мазер" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target"><span>Беларуская</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%9C%D0%B0%D0%B7%D0%B5%D1%80" title="Мазер – Bulgarian" lang="bg" hreflang="bg" data-title="Мазер" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/M%C3%A0ser" title="Màser – Catalan" lang="ca" hreflang="ca" data-title="Màser" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Maser" title="Maser – Czech" lang="cs" hreflang="cs" data-title="Maser" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Maser" title="Maser – Danish" lang="da" hreflang="da" data-title="Maser" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Maser" title="Maser – German" lang="de" hreflang="de" data-title="Maser" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/M%C3%A1ser" title="Máser – Spanish" lang="es" hreflang="es" data-title="Máser" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Masero" title="Masero – Esperanto" lang="eo" hreflang="eo" data-title="Masero" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Maser" title="Maser – Basque" lang="eu" hreflang="eu" data-title="Maser" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%85%DB%8C%D8%B2%D8%B1" title="میزر – Persian" lang="fa" hreflang="fa" data-title="میزر" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Maser" title="Maser – French" lang="fr" hreflang="fr" data-title="Maser" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/M%C3%A9asar" title="Méasar – Irish" lang="ga" hreflang="ga" data-title="Méasar" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/M%C3%A1ser" title="Máser – Galician" lang="gl" hreflang="gl" data-title="Máser" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%A9%94%EC%9D%B4%EC%A0%80_(%EA%B4%91%ED%95%99_%EA%B8%B0%EA%B8%B0)" title="메이저 (광학 기기) – Korean" lang="ko" hreflang="ko" data-title="메이저 (광학 기기)" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D5%84%D5%A1%D5%A6%D5%A5%D6%80_(%D5%B8%D6%82%D5%AA%D5%A5%D5%B2%D5%A1%D6%81%D5%B8%D6%82%D6%81%D5%AB%D5%B9)" title="Մազեր (ուժեղացուցիչ) – Armenian" lang="hy" hreflang="hy" data-title="Մազեր (ուժեղացուցիչ)" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%AE%E0%A5%87%E0%A4%B8%E0%A4%B0" title="मेसर – Hindi" lang="hi" hreflang="hi" data-title="मेसर" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Maser" title="Maser – Croatian" lang="hr" hreflang="hr" data-title="Maser" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Maser" title="Maser – Indonesian" lang="id" hreflang="id" data-title="Maser" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Maser" title="Maser – Italian" lang="it" hreflang="it" data-title="Maser" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-kn mw-list-item"><a href="https://kn.wikipedia.org/wiki/%E0%B2%AE%E0%B3%87%E0%B2%B8%E0%B2%B0%E0%B3%8D" title="ಮೇಸರ್ – Kannada" lang="kn" hreflang="kn" data-title="ಮೇಸರ್" data-language-autonym="ಕನ್ನಡ" data-language-local-name="Kannada" class="interlanguage-link-target"><span>ಕನ್ನಡ</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%9C%D0%B0%D0%B7%D0%B5%D1%80" title="Мазер – Kazakh" lang="kk" hreflang="kk" data-title="Мазер" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-ky mw-list-item"><a href="https://ky.wikipedia.org/wiki/%D0%9C%D0%B0%D0%B7%D0%B5%D1%80" title="Мазер – Kyrgyz" lang="ky" hreflang="ky" data-title="Мазер" data-language-autonym="Кыргызча" data-language-local-name="Kyrgyz" class="interlanguage-link-target"><span>Кыргызча</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/M%C3%A9zer" title="Mézer – Hungarian" lang="hu" hreflang="hu" data-title="Mézer" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%AE%E0%B5%87%E0%B4%B8%E0%B5%BC" title="മേസർ – Malayalam" lang="ml" hreflang="ml" data-title="മേസർ" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%9C%D0%B0%D0%B7%D0%B5%D1%80" title="Мазер – Mongolian" lang="mn" hreflang="mn" data-title="Мазер" data-language-autonym="Монгол" data-language-local-name="Mongolian" class="interlanguage-link-target"><span>Монгол</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Maser_(straling)" title="Maser (straling) – Dutch" lang="nl" hreflang="nl" data-title="Maser (straling)" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E3%83%A1%E3%83%BC%E3%82%B6%E3%83%BC" title="メーザー – Japanese" lang="ja" hreflang="ja" data-title="メーザー" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Maser" title="Maser – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Maser" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Maser" title="Maser – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Maser" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-om mw-list-item"><a href="https://om.wikipedia.org/wiki/Shifgumasii" title="Shifgumasii – Oromo" lang="om" hreflang="om" data-title="Shifgumasii" data-language-autonym="Oromoo" data-language-local-name="Oromo" class="interlanguage-link-target"><span>Oromoo</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Maser" title="Maser – Polish" lang="pl" hreflang="pl" data-title="Maser" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Maser_(radia%C3%A7%C3%A3o)" title="Maser (radiação) – Portuguese" lang="pt" hreflang="pt" data-title="Maser (radiação)" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Maser" title="Maser – Romanian" lang="ro" hreflang="ro" data-title="Maser" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-rue mw-list-item"><a href="https://rue.wikipedia.org/wiki/%D0%9C%D0%B0%D1%81%D0%B5%D1%80" title="Масер – Rusyn" lang="rue" hreflang="rue" data-title="Масер" data-language-autonym="Русиньскый" data-language-local-name="Rusyn" class="interlanguage-link-target"><span>Русиньскый</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9C%D0%B0%D0%B7%D0%B5%D1%80" title="Мазер – Russian" lang="ru" hreflang="ru" data-title="Мазер" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Maser" title="Maser – Simple English" lang="en-simple" hreflang="en-simple" data-title="Maser" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Maser_(gener%C3%A1tor)" title="Maser (generátor) – Slovak" lang="sk" hreflang="sk" data-title="Maser (generátor)" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Maser" title="Maser – Finnish" lang="fi" hreflang="fi" data-title="Maser" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Maser" title="Maser – Swedish" lang="sv" hreflang="sv" data-title="Maser" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%AE%E0%AF%87%E0%AE%9A%E0%AE%B0%E0%AF%8D" title="மேசர் – Tamil" lang="ta" hreflang="ta" data-title="மேசர்" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Mazer" title="Mazer – Turkish" lang="tr" hreflang="tr" data-title="Mazer" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9C%D0%B0%D0%B7%D0%B5%D1%80" title="Мазер – Ukrainian" lang="uk" hreflang="uk" data-title="Мазер" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Maser" title="Maser – Vietnamese" lang="vi" hreflang="vi" data-title="Maser" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E6%BF%80%E5%BE%AE%E6%B3%A2" title="激微波 – Chinese" lang="zh" hreflang="zh" data-title="激微波" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li></ul> </section> </div> <div class="minerva-footer-logo"> <img src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" alt="Wikipedia" width="120" height="18" style="width: 7.5em; height: 1.125em;"/> <ul id="footer-icons" class="footer-icons"> <li id="footer-copyrightico"><a href="https://www.wikimedia.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><picture><source media="(min-width: 500px)" srcset="/static/images/footer/wikimedia-button.svg" width="84" height="29"><img src="/static/images/footer/wikimedia.svg" width="25" height="25" alt="Wikimedia 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