Editing Holography (section)

==History==
[[File:IntroductionToHolography1972.ogv|thumb|thumbtime=40|''Introduction to Holography'' (1972 educational film)]]
The [[Magyars|Hungarian]]-[[British people|British]] physicist [[Dennis Gabor]] invented holography in 1948 while he was looking for a way to improve [[image resolution]] in [[electron microscope]]s.<ref>{{cite journal |last1 = Gabor |first1 = Dennis |author-link = Dennis Gabor |year = 1948 |title = A new microscopic principle |journal = Nature |volume = 161 |issue = 4098 |pages = 777–8 |doi=10.1038/161777a0 |bibcode = 1948Natur.161..777G |pmid=18860291 |s2cid = 4121017 |doi-access = free }}</ref><ref>{{Cite journal |doi = 10.1098/rspa.1949.0075 |first = Dennis |last = Gabor |year = 1949 |title = Microscopy by reconstructed wavefronts |journal = Proceedings of the Royal Society |volume = 197 |pages = 454–487 |issue = 1051 |bibcode = 1949RSPSA.197..454G |s2cid = 123187722 |doi-access = free}}</ref><ref name=FieldGuideHistory>{{Cite book |last=Blanche |first=Pierre-Alexandre |title=Field guide to holography |date=2014 |publisher=SPIE Press |isbn=978-0-8194-9957-8 |series=SPIE field guides |location=Bellingham, Wash|page=1}}</ref> Gabor's work was built on pioneering work in the field of [[X-ray microscopy]] by other scientists including [[Mieczysław Wolfke]] in 1920 and [[William Lawrence Bragg]] in 1939.<ref name="Hariharan 1996">{{cite book |last1=Hariharan |first1=P. |title=Optical Holography |date=1996 |publisher=Cambridge University Press |location=Cambridge |isbn=9780521433488}}</ref> The formulation of holography was an unexpected result of Gabor's research into improving electron microscopes at the [[British Thomson-Houston]] Company (BTH) in [[Rugby, Warwickshire|Rugby]], England, and the company filed a [[patent]] in December 1947 (patent GB685286). The technique as originally invented is still used in electron microscopy, where it is known as [[electron holography]]. Gabor was awarded the [[Nobel Prize in Physics]] in 1971 "for his invention and development of the holographic method".<ref>{{cite web |url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1971/ |title=The Nobel Prize in Physics 1971 |publisher=Nobelprize.org |access-date=2012-04-21}}</ref>

[[File:III-BIBI BEI BOB.jpg|thumb|Horizontal symmetric text, by [[Dieter Jung (artist)|Dieter Jung]]]]
Optical holography did not really advance until the development of the [[laser]] in 1960. The development of the laser enabled the first practical optical holograms that recorded 3D objects to be made in 1962 by [[Yuri Denisyuk]] in the Soviet Union<ref name="denisyuk">{{Cite journal |title = On the reflection of optical properties of an object in a wave field of light scattered by it |last = Denisyuk |first = Yuri N. |author-link = Yuri Denisyuk|journal = [[Doklady Akademii Nauk SSSR]] |volume = 144|pages = 1275–1278|year = 1962|issue = 6}}</ref> and by [[Emmett Leith]] and [[Juris Upatnieks]] at the [[University of Michigan]], US.<ref name="leith">{{Cite journal |title = Reconstructed wavefronts and communication theory|author = Leith, E.N.|author2=Upatnieks, J.|journal = J. Opt. Soc. Am. |volume = 52|pages = 1123–1130|year = 1962|doi =10.1364/JOSA.52.001123| issue = 10|bibcode = 1962JOSA...52.1123L}}</ref>

Early optical holograms used [[silver halide]] photographic emulsions as the recording medium. They were not very efficient as the produced [[diffraction grating]] absorbed much of the incident light. Various methods of converting the variation in transmission to a variation in refractive index (known as "bleaching") were developed which enabled much more efficient holograms to be produced.<ref>{{cite journal |last1 = Upatnieks |first1 = J |last2 = Leonard |first2 = C |year = 1969 |title = Diffraction efficiency of bleached, photographically recorded interference patterns |journal = Applied Optics |volume = 8 |issue = 1 |pages = 85–89 |doi = 10.1364/ao.8.000085 |pmid = 20072177 |bibcode = 1969ApOpt...8...85U }}</ref><ref>{{cite journal |last1 = Graube |first1 = A |year = 1974 |title = Advances in bleaching methods for photographically recorded holograms |journal = Applied Optics |volume = 13 |issue = 12 |pages = 2942–6 |doi = 10.1364/ao.13.002942 |pmid = 20134813 |bibcode = 1974ApOpt..13.2942G }}</ref><ref>{{cite journal |last1 = Phillips |first1 = N. J. |last2 = Porter |first2 = D. |year = 1976 |title = An advance in the processing of holograms |journal = Journal of Physics E: Scientific Instruments |volume = 9 |issue = 8 |page = 631 |doi = 10.1088/0022-3735/9/8/011 |bibcode = 1976JPhE....9..631P }}</ref>

A major advance in the field of holography was made by [[Stephen Benton]], who invented a way to create holograms that can be viewed with natural light instead of lasers. These are called [[rainbow hologram]]s.<ref name=FieldGuideHistory />