Editing Optics (section)

==Modern optics==
{{Main|Optical physics|Optical engineering}}

''Modern optics'' encompasses the areas of optical science and engineering that became popular in the 20th century. These areas of optical science typically relate to the electromagnetic or quantum properties of light but do include other topics. A major subfield of modern optics, [[quantum optics]], deals with specifically quantum mechanical properties of light. Quantum optics is not just theoretical; some modern devices, such as lasers, have principles of operation that depend on quantum mechanics. Light detectors, such as [[photomultiplier]]s and [[channeltron]]s, respond to individual photons. Electronic [[image sensor]]s, such as [[Charge-coupled device|CCDs]], exhibit [[shot noise]] corresponding to the statistics of individual photon events. [[Light-emitting diode]]s and [[photovoltaic cell]]s, too, cannot be understood without quantum mechanics. In the study of these devices, quantum optics often overlaps with [[quantum electronics]].<ref>{{cite book |last1= Walls |first1= Daniel Frank |last2= Milburn |first2= G. J. |date= 1994 |title= Quantum Optics |publisher= Springer |author-link1= Daniel Frank Walls}}</ref>

Specialty areas of optics research include the study of how light interacts with specific materials as in [[crystal optics]] and [[metamaterial]]s. Other research focuses on the phenomenology of electromagnetic waves as in [[optical vortex|singular optics]], [[non-imaging optics]], [[non-linear optics]], statistical optics, and [[radiometry]]. Additionally, [[computer engineer]]s have taken an interest in [[integrated optics]], [[machine vision]], and [[photonic computing]] as possible components of the "next generation" of computers.<ref>{{cite book |last= McAulay |first= Alastair D. |date= 16 January 1991 |title= Optical Computer Architectures: The Application of Optical Concepts to Next Generation Computers |publisher= Wiley |isbn= 978-0-471-63242-9}}</ref>

Today, the pure science of optics is called optical science or [[optical physics]] to distinguish it from applied optical sciences, which are referred to as [[optical engineering]]. Prominent subfields of optical engineering include [[lighting|illumination engineering]], [[photonics]], and [[optoelectronics]] with practical applications like [[Optical lens design|lens design]], [[Fabrication and testing (optical components)|fabrication and testing of optical components]], and [[image processing]]. Some of these fields overlap, with nebulous boundaries between the subjects' terms that mean slightly different things in different parts of the world and in different areas of industry. A professional community of researchers in nonlinear optics has developed in the last several decades due to advances in laser technology.<ref>{{cite book |last= Shen |first= Y. R. |date= 1984 |title= The Principles of Nonlinear Optics |publisher= Wiley-Interscience |location= New York |isbn= 978-0-471-88998-4}}
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===Lasers===
{{Main|Laser}}
[[File:Military laser experiment.jpg|thumb|Experiments such as this one with high-power [[laser]]s are part of the modern optics research.]]
A laser is a device that emits light, a kind of electromagnetic radiation, through a process called ''[[stimulated emission]]''. The term ''laser'' is an [[acronym]] for {{gloss|Light Amplification by Stimulated Emission of Radiation}}.<ref>{{cite web|access-date=2008-05-15|url=http://dictionary.reference.com/browse/laser|title=laser|publisher=Reference.com|url-status=live|archive-url=https://web.archive.org/web/20080331135923/http://dictionary.reference.com/browse/laser|archive-date=2008-03-31}}</ref> Laser light is usually spatially [[coherence (physics)|coherent]], which means that the light either is emitted in a narrow, [[Beam divergence|low-divergence beam]], or can be converted into one with the help of optical components such as lenses. Because the microwave equivalent of the laser, the ''maser'', was developed first, devices that emit microwave and [[Radio frequency|radio]] frequencies are usually called ''masers''.<ref>[http://nobelprize.org/physics/laureates/1964/townes-lecture.pdf Charles H. Townes – Nobel Lecture] {{webarchive|url=https://web.archive.org/web/20081011162942/http://nobelprize.org/physics/laureates/1964/townes-lecture.pdf |date=2008-10-11 }}. nobelprize.org</ref>

[[File:The VLT’s Artificial Star.jpg|thumb|left|[[Very Large Telescope|VLT]]'s laser guide star<ref>{{cite news|title=The VLT's Artificial Star|url=http://www.eso.org/public/images/potw1425a/|access-date=25 June 2014|work=ESO Picture of the Week|url-status=live|archive-url=https://web.archive.org/web/20140703151816/http://www.eso.org/public/images/potw1425a/|archive-date=3 July 2014}}</ref>]]

The first working laser was demonstrated on 16 May 1960 by [[Theodore Maiman]] at [[Hughes Research Laboratories]].<ref>{{cite web|access-date=2008-05-15|url=http://www.press.uchicago.edu/Misc/Chicago/284158_townes.html|title=The first laser|publisher=University of Chicago|author=C.H. Townes|url-status=live|archive-url=https://web.archive.org/web/20080517082709/http://www.press.uchicago.edu/Misc/Chicago/284158_townes.html|archive-date=2008-05-17}}</ref> When first invented, they were called "a solution looking for a problem".<ref>{{cite book|title=A Century of Nature: Twenty-One Discoveries that Changed Science and the World|author=C.H. Townes|author-link=Charles Hard Townes|chapter=The first laser|chapter-url=http://www.press.uchicago.edu/Misc/Chicago/284158_townes.html|editor1=Laura Garwin|editor1-link= Laura Garwin |editor2=Tim Lincoln|publisher=University of Chicago Press|year=2003|pages=[https://archive.org/details/centuryofnaturet00garw/page/107 107–112]|isbn=978-0-226-28413-2|url=https://archive.org/details/centuryofnaturet00garw/page/107}}</ref> Since then, lasers have become a multibillion-dollar industry, finding utility in thousands of highly varied applications. The first application of lasers visible in the daily lives of the general population was the supermarket [[barcode]] scanner, introduced in 1974.<ref>[http://www.denso-wave.com/en/adcd/fundamental/barcode/index.html What is a bar code?] {{webarchive|url=https://web.archive.org/web/20120423030551/http://www.denso-wave.com/en/adcd/fundamental/barcode/index.html |date=2012-04-23 }} denso-wave.com</ref> The [[laserdisc]] player, introduced in 1978, was the first successful consumer product to include a laser, but the [[compact disc]] player was the first laser-equipped device to become truly common in consumers' homes, beginning in 1982.<ref name=BBC6950933>{{cite news|url=http://news.bbc.co.uk/2/hi/technology/6950933.stm|title=How the CD was developed|work=BBC News|date=2007-08-17|access-date=2007-08-17|url-status=live|archive-url=https://web.archive.org/web/20120107064451/http://news.bbc.co.uk/2/hi/technology/6950933.stm|archive-date=2012-01-07}}</ref> These [[optical storage]] devices use a [[semiconductor laser]] less than a millimetre wide to scan the surface of the disc for data retrieval. [[Fibre-optic communication]] relies on lasers to transmit large amounts of information at the speed of light. Other common applications of lasers include [[laser printers]] and [[laser pointer]]s. Lasers are used in medicine in areas such as [[bloodless surgery]], [[laser eye surgery]], and [[laser capture microdissection]] and in military applications such as [[Airborne Laser|missile defence systems]], [[DIRCM|electro-optical countermeasures (EOCM)]], and [[lidar]]. Lasers are also used in [[holograms]], [[bubblegram]]s, [[laser lighting display|laser light shows]], and [[laser hair removal]].<ref>{{cite book|author1=J. Wilson  |author2=J.F.B. Hawkes |name-list-style=amp |year=1987|title=Lasers: Principles and Applications, Prentice Hall International Series in Optoelectronics|publisher=Prentice Hall|isbn=978-0-13-523697-0}}</ref>

===Kapitsa–Dirac effect===
The [[Kapitsa–Dirac effect]] causes beams of particles to diffract as the result of meeting a standing wave of light. Light can be used to position matter using various phenomena (see [[optical tweezers]]).