Editing Laser (section)

=== Recent innovations ===
[[File:History of laser intensity.svg|thumb|Graph showing the history of maximum laser pulse intensity since 1960]]

Since the early period of laser history, laser research has produced a variety of improved and specialized laser types, optimized for different performance goals, including:
* new wavelength bands
* maximum average output power
* maximum peak pulse [[energy]]
* maximum peak pulse [[power (physics)|power]]
* minimum output pulse duration
* minimum linewidth
* maximum power efficiency
* minimum cost

Research on improving these aspects of lasers continues to this day.

In 2015, researchers made a white laser, whose light is modulated by a synthetic nanosheet made out of zinc, cadmium, sulfur, and selenium that can emit red, green, and blue light in varying proportions, with each wavelength spanning 191&nbsp;nm.<ref>{{Cite web |url=https://www.popsci.com/scientists-have-finally-made-white-laser/ |title=For The First Time, A Laser That Shines Pure White |website=Popular Science |date=March 18, 2019 |access-date=December 16, 2019 |archive-date=December 16, 2019 |archive-url=https://web.archive.org/web/20191216085708/https://www.popsci.com/scientists-have-finally-made-white-laser/ |url-status=live}}</ref><ref>{{Cite web |url=https://phys.org/news/2015-07-world-white-lasers.html |title=Researchers demonstrate the world's first white lasers |website=phys.org |access-date=December 16, 2019 |archive-date=December 16, 2019 |archive-url=https://web.archive.org/web/20191216085720/https://phys.org/news/2015-07-world-white-lasers.html |url-status=live}}</ref><ref>{{Cite web |url=https://gizmodo.com/scientists-finally-created-a-white-laser-and-it-could-l-1721027962/amp |title=Scientists Finally Created a White Laser—and It Could Light Your Home |website=gizmodo.com |date=July 30, 2015 |access-date=December 16, 2019 |archive-date=December 16, 2019 |archive-url=https://web.archive.org/web/20191216085712/https://gizmodo.com/scientists-finally-created-a-white-laser-and-it-could-l-1721027962/amp |url-status=live}}</ref>

In 2017, researchers at the [[Delft University of Technology]] demonstrated an [[Josephson effect#The AC Josephson effect|AC Josephson junction]] microwave laser.<ref>{{cite web |title=Researchers demonstrate new type of laser |url=https://phys.org/news/2017-03-laser.html |website=Phys.org |access-date=4 March 2017 |archive-date=March 3, 2017 |archive-url=https://web.archive.org/web/20170303164343/https://phys.org/news/2017-03-laser.html |url-status=live}}</ref> Since the laser operates in the superconducting regime, it is more stable than other semiconductor-based lasers. The device has the potential for applications in [[quantum computing]].<ref>{{cite journal |last1=Cassidy|first1=M. C. |last2=Bruno |first2=A. |last3=Rubbert |first3=S. |last4=Irfan |first4=M. |last5=Kammhuber |first5=J. |last6=Schouten |first6=R.N. |last7=Akhmerov |first7=A.R. |last8=Kouwenhoven |first8=L.P. |title=Demonstration of an ac Josephson junction laser |journal=Science |date=March 2, 2017 |volume=355 |issue=6328 |pages=939–942 |doi=10.1126/science.aah6640 |pmid=28254938 |arxiv=1703.05404 |bibcode=2017Sci...355..939C |s2cid=1364541}}</ref> In 2017, researchers at the [[Technical University of Munich]] demonstrated the smallest [[mode locking]] laser capable of emitting pairs of phase-locked picosecond laser pulses with a repetition frequency up to 200&nbsp;GHz.<ref name="nwpl">{{cite journal|title=Long-term mutual phase locking of picosecond pulse pairs generated by a semiconductor nanowire laser |first1=B. |last1=Mayer |first2=A. |last2=Regler |first3=S. |last3=Sterzl |first4=T. |last4=Stettner |first5=G. |last5=Koblmüller |first6=M. |last6=Kaniber |first7=B. |last7=Lingnau |first8=K. |last8=Lüdge |first9=J.J. |last9=Finley |date=May 23, 2017 |journal=Nature Communications |volume=8 |pages=15521 |doi=10.1038/ncomms15521 |pmid=28534489 |pmc=5457509 |arxiv=1603.02169 |bibcode=2017NatCo...815521M}}</ref>

In 2017, researchers from the [[Physikalisch-Technische Bundesanstalt]] (PTB), together with US researchers from [[JILA]], a joint institute of the National Institute of Standards and Technology (NIST) and the [[University of Colorado Boulder]], established a new world record by developing an erbium-doped fiber laser with a linewidth of only 10{{nbsp}}millihertz.<ref>{{cite press release |author=Erika Schow |url=http://www.ptb.de/cms/en/presseaktuelles/journalisten/news-press-releases/press-release.html |title=The Physikalisch-Technische Bundesanstalt has developed a laser with a linewidth of only 10 mHz |date=June 29, 2017 |url-status=dead |archive-url=https://web.archive.org/web/20170703235028/http://www.ptb.de/cms/en/presseaktuelles/journalisten/news-press-releases/press-release.html |archive-date=2017-07-03}}</ref><ref>{{cite journal |title=1.5 μm Lasers with Sub-10 mHz Linewidth |first1=D.G. |last1=Matei |first2=T. |last2=Legero |first3=S. |last3=Häfner |first4=C. |last4=Grebing |first5=R. |last5=Weyrich |first6=W. |last6=Zhang |first7=L. |last7=Sonderhouse |first8=J.M. |last8=Robinson |first9=J. |last9=Ye |display-authors=3 |journal=Phys. Rev. Lett. |volume=118 |page=263202 |issue=26 |date=30 June 2017 |doi=10.1103/PhysRevLett.118.263202 |pmid=28707932 |arxiv=1702.04669 |bibcode=2017PhRvL.118z3202M |s2cid=206293342}}</ref>