Editing Laser (section)

== Terminology ==
The first device using amplification by stimulated emission operated at [[microwave]] frequencies, and was called a ''[[maser]]'', for "microwave amplification by stimulated emission of radiation".<ref>{{Cite book |last=Heilbron |first=John L. |url=https://archive.org/details/oxfordcompaniont0000unse_s7n3 |title=The Oxford Companion to the History of Modern Science |date=2003-03-27 |publisher=[[Oxford University Press]] |isbn=978-0-19-974376-6 |pages=[https://archive.org/details/oxfordcompaniont0000unse_s7n3/page/446/mode/2up 447] |language=en |url-access=registration}}</ref> When similar [[Visible spectrum|optical]] devices were developed they were first called ''optical masers'', until "microwave" was replaced by "light" in the acronym, to become ''laser''.<ref>{{Cite book |last=Bertolotti |first=Mario |url= |title=The History of the Laser |date=2004-10-01 |publisher=[[CRC Press]] |isbn=978-1-4200-3340-3 |pages=[https://books.google.com/books?id=JObDnEtzMJUC 215], [https://books.google.com/books?id=JObDnEtzMJUC 218]–[https://books.google.com/books?id=JObDnEtzMJUC 219] |language=en}}</ref><ref>{{cite web |last=Hall |first=Carla |title=Inventor Beams Over Laser Patents : After 30 Years, Gordon Gould Gets Credit He Deserves |website=Los Angeles Times |date=1987-12-17 |url=https://www.latimes.com/archives/la-xpm-1987-12-17-vw-29544-story.html |access-date=2024-11-01}}</ref><ref>{{cite web |last=II |first=Thomas H. Maugh |title=Gordon Gould, 85; Physicist Finally Got His Due for the Laser |website=Los Angeles Times |date=2005-09-21 |url=https://www.latimes.com/archives/la-xpm-2005-sep-21-me-gould21-story.html |access-date=2024-11-01}}</ref>

Today, all such devices operating at frequencies higher than microwaves (approximately above 300 [[Hertz|GHz]]) are called lasers (e.g. ''infrared lasers'', ''ultraviolet lasers'', ''[[X-ray laser]]s'', ''[[gamma-ray laser]]s''), whereas devices operating at [[microwave]] or lower [[Radio frequency|radio frequencies]] are called masers.<ref>{{Cite book |last=McAulay |first=Alastair D. |url= |title=Military Laser Technology for Defense: Technology for Revolutionizing 21st Century Warfare |date=2011-05-31 |publisher=[[John Wiley & Sons]] |isbn=978-0-470-25560-5 |page=[https://books.google.com/books?id=6nFguMVUXAgC&pg=PA127 127] |language=en}}</ref><ref>{{Cite book |last=Renk |first=Karl F. |url= |title=Basics of Laser Physics: For Students of Science and Engineering |date=2012-02-09 |publisher=[[Springer Science & Business Media]] |isbn=978-3-642-23565-8 |page=[https://books.google.com/books?id=uN6RDgAAQBAJ&pg=PA4 4] |language=en}}</ref>

The [[back-formation|back-formed]] verb "[[wikt:en:lase#English|to lase]]" is frequently used in the field, meaning "to give off coherent light," especially about the [[Active laser medium|gain medium]] of a laser;<ref>{{Cite web |title=LASE |url=https://www.collinsdictionary.com/dictionary/english/lase# |access-date=January 6, 2024 |website=[[Collins English Dictionary#CollinsDictionary.com|Collins Dictionary]]}}</ref> when a laser is operating, it is said to be "[[wikt:en:lasing#English|lasing]]".<ref>{{Cite web |title=LASING |url=https://www.collinsdictionary.com/dictionary/english/lasing# |access-date=January 6, 2024 |website=[[Collins English Dictionary#CollinsDictionary.com|Collins Dictionary]]}}</ref> The terms ''laser'' and ''maser'' are also used for naturally occurring coherent emissions, as in ''[[astrophysical maser]]'' and ''[[atom laser]]''.<ref>{{cite journal |last1=Strelnitski |first1=Vladimir |year=1997 |title=Masers, Lasers and the Interstellar Medium |journal=Astrophysics and Space Science |volume=252 |issue=1–2 |pages=279–287 |bibcode=1997Ap&SS.252..279S |doi=10.1023/A:1000892300429 |s2cid=115181195}}</ref><ref name="Biographical Memoirs" />

A laser that produces light by itself is technically an optical oscillator rather than an [[optical amplifier]] as suggested by the acronym.<ref>{{Cite book |last1=Al-Amri |first1=Mohammad D. |url= |title=Optics in Our Time |last2=El-Gomati |first2=Mohamed |last3=Zubairy |first3=M. Suhail |date=2016-12-12 |publisher=[[Springer Science+Business Media|Springer]] |isbn=978-3-319-31903-2 |page=[https://books.google.com/books?id=GtlCDwAAQBAJ&pg=PA76 76] |language=en}}</ref> It has been humorously noted that the acronym LOSER, for "light oscillation by stimulated emission of radiation", would have been more correct.<ref name="Biographical Memoirs">{{cite book |last1=Chu |first1=Steven |author-link=Steven Chu |last2=Townes |first2=Charles |author-link2=Charles Hard Townes |editor=Edward P. Lazear |title=Biographical Memoirs |year=2003 |volume=83 |publisher=National Academy of Sciences |isbn=978-0-309-08699-8 |page=202 |chapter=Arthur Schawlow |url=http://www.nap.edu/openbook/030908699X/html/202.html }}</ref><ref>{{Cite book |last=Hecht |first=Jeff |url= |title=Understanding Lasers: An Entry-Level Guide |date=2018-12-27 |publisher=[[John Wiley & Sons]] |isbn=978-1-119-31064-8 |page=[https://books.google.com/books?id=2nJ6DwAAQBAJ&pg=PA201 201] |language=en}}</ref> Some sources<ref>{{Cite web |title=UCSB Science Line |url=http://scienceline.ucsb.edu/getkey.php?key=1050 |access-date=2024-12-09 |website=scienceline.ucsb.edu}}</ref><ref>{{Cite journal |last=Feldmann |first=Sascha |date=2023-08-02 |title=Taming the tiniest of lasers: Electrically pumped amplified spontaneous emission from nanocrystals |url=https://linkinghub.elsevier.com/retrieve/pii/S2590238523003119 |journal=Matter |language=English |volume=6 |issue=8 |pages=2568–2570 |doi=10.1016/j.matt.2023.06.022 |issn=2590-2393}}</ref> refer to the word laser as an [[anacronym]], meaning an acronym so widely used as a noun that it is no longer considered an abbreviation.<ref>{{Cite web |title=anacronym |url=https://www.wordsmith.org/words/anacronym.html |access-date=2024-12-09 |website=Wordsmith.org}}</ref>