Editing Optics (section)

==History==
{{Main|History of optics}}
{{See also|Timeline of electromagnetism and classical optics}}
[[File:Nimrud lens British Museum.jpg|thumb|right|The Nimrud lens]]
Optics began with the development of lenses by the [[ancient Egypt]]ians and [[Mesopotamia]]ns. The earliest known lenses, made from polished [[crystal]], often [[quartz]], date from as early as 2000&nbsp;BC from [[Crete]] (Archaeological Museum of Heraclion, Greece). Lenses from [[Rhodes]] date around 700&nbsp;BC, as do [[Assyria]]n lenses such as the [[Nimrud lens]].<ref>{{cite news |url=http://news.bbc.co.uk/1/hi/sci/tech/380186.stm |title=World's oldest telescope? |work=BBC News |date=July 1, 1999 |access-date=Jan 3, 2010 |url-status=live |archive-url=https://web.archive.org/web/20090201185740/http://news.bbc.co.uk/1/hi/sci/tech/380186.stm |archive-date=February 1, 2009 }}</ref> The [[ancient Roman]]s and [[Ancient Greece|Greeks]] filled glass spheres with water to make lenses. These practical developments were followed by the development of theories of light and vision by ancient [[Greek philosophy|Greek]] and [[Indian philosophy|Indian]] philosophers, and the development of [[geometrical optics]] in the [[Greco-Roman world]]. The word ''optics'' comes from the [[ancient Greek]] word {{lang|grc|ὀπτική}}, {{Transliteration|grc|optikē}} {{gloss|appearance, look}}.<ref>{{cite book|title=The Concise Oxford Dictionary of English Etymology|year=1996|author=T.F. Hoad|isbn=978-0-19-283098-2|url=https://archive.org/details/conciseoxforddic00tfho}}</ref>

Greek philosophy on optics broke down into two opposing theories on how vision worked, the [[intromission theory]] and the [[emission theory (vision)|emission theory]].<ref>[http://www.stanford.edu/class/history13/earlysciencelab/body/eyespages/eye.html A History Of The Eye] {{webarchive|url=https://web.archive.org/web/20120120085632/http://www.stanford.edu/class/history13/earlysciencelab/body/eyespages/eye.html |date=2012-01-20 }}. stanford.edu. Retrieved 2012-06-10.</ref> The intromission approach saw vision as coming from objects casting off copies of themselves (called eidola) that were captured by the eye. With many propagators including [[Democritus]], [[Epicurus]], [[Aristotle]] and their followers, this theory seems to have some contact with modern theories of what vision really is, but it remained only speculation lacking any experimental foundation.

[[Plato]] first articulated the [[Emission theory (vision)|emission theory]], the idea that [[visual perception]] is accomplished by rays emitted by the eyes. He also commented on the [[parity (physics)|parity]] reversal of mirrors in ''[[Timaeus (dialogue)|Timaeus]]''.<ref>{{cite book|title=A manual of greek mathematics|author=T.L. Heath|publisher=Courier Dover Publications|isbn=978-0-486-43231-1|pages=181–182|year=2003}}</ref> Some hundred years later, [[Euclid]] (4th–3rd century BC) wrote a treatise entitled ''[[Euclid#Other works|Optics]]'' where he linked vision to [[geometry]], creating ''geometrical optics''.<ref>{{cite book |author=William R. Uttal |title=Visual Form Detection in 3-Dimensional Space |url=https://books.google.com/books?id=rhVOVKp0-5wC&pg=PA25 |year=1983 |publisher=Psychology Press |isbn=978-0-89859-289-4 |pages=25– |url-status=live |archive-url=https://web.archive.org/web/20160503123615/https://books.google.com/books?id=rhVOVKp0-5wC&pg=PA25 |archive-date=2016-05-03 }}</ref> He based his work on Plato's emission theory wherein he described the mathematical rules of [[perspective (graphical)|perspective]] and described the effects of [[refraction]] qualitatively, although he questioned that a beam of light from the eye could instantaneously light up the stars every time someone blinked.<ref>{{cite book|author=Euclid|title=The Arabic version of Euclid's optics = Kitāb Uqlīdis fī ikhtilāf al-manāẓir|editor=Elaheh Kheirandish|publisher=New York: Springer|year=1999|isbn=978-0-387-98523-7|url-access=registration|url=https://archive.org/details/arabicversionofe0000eucl}}</ref>  Euclid stated the principle of shortest trajectory of light, and considered multiple reflections on flat and spherical mirrors.
[[Ptolemy]], in his treatise ''[[Ptolemy#Optics|Optics]]'', held an extramission-intromission theory of vision: the rays (or flux) from the eye formed a cone, the vertex being within the eye, and the base defining the visual field. The rays were sensitive, and conveyed information back to the observer's intellect about the distance and orientation of surfaces. He summarized much of Euclid and went on to describe a way to measure the [[angle of refraction]], though he failed to notice the empirical relationship between it and the angle of incidence.<ref name=Ptolemy>{{cite book |title=Ptolemy's theory of visual perception: an English translation of the Optics with introduction and commentary |author=Ptolemy |editor=A. Mark Smith |publisher=DIANE Publishing |year=1996 |isbn=978-0-87169-862-9}}</ref> [[Plutarch]] (1st–2nd century AD) described multiple reflections on spherical mirrors and discussed the creation of magnified and reduced images, both real and imaginary, including the case of [[chirality]] of the images.
[[File:Ibn Sahl manuscript.jpg|thumb|right|upright|Reproduction of a page of [[Ibn Sahl (mathematician)|Ibn Sahl]]'s manuscript showing his knowledge of [[Snell's law|the law of refraction]] ]]
During the [[Middle Ages]], Greek ideas about optics were resurrected and extended by writers in the [[Muslim world]]. One of the earliest of these was [[Al-Kindi]] ({{Circa|801}}–873) who wrote on the merits of Aristotelian and Euclidean ideas of optics, favouring the emission theory since it could better quantify optical phenomena.<ref>Adamson, Peter (2006). "Al-Kindi¯ and the reception of Greek philosophy". In Adamson, Peter; Taylor, R.. The Cambridge companion to Arabic philosophy. Cambridge University Press. p. 45. {{ISBN|978-0-521-52069-0}}.</ref> In 984, the [[Persia]]n mathematician [[Ibn Sahl (mathematician)|Ibn Sahl]] wrote the treatise "On burning mirrors and lenses", correctly describing a law of refraction equivalent to Snell's law.<ref name=j1>{{cite journal |doi=10.1086/355456 |last=Rashed |first=Roshdi |title=A pioneer in anaclastics: Ibn Sahl on burning mirrors and lenses |journal=Isis |volume=81 |issue = 3 |year=1990 |pages=464–491 |jstor=233423|s2cid=144361526 }}</ref> He used this law to compute optimum shapes for lenses and [[curved mirror]]s. In the early 11th century, [[Ibn al-Haytham|Alhazen (Ibn al-Haytham)]] wrote the ''[[Book of Optics]]'' (''Kitab al-manazir'') in which he explored reflection and refraction and proposed a new system for explaining vision and light based on observation and experiment.<ref>{{multiref2 | {{cite book |editor1-last=Hogendijk |editor1-first=Jan P. |editor2-last=Sabra |editor2-first=Abdelhamid I. |year=2003|title=The Enterprise of Science in Islam: New Perspectives |pages=85–118 |publisher=MIT Press |isbn=978-0-262-19482-2 |oclc=50252039}} | {{cite book |author=G. Hatfield |contribution=Was the Scientific Revolution Really a Revolution in Science? |url=https://books.google.com/books?id=Kl1COWj9ubAC&pg=PA489 |isbn=978-90-04-10119-7 |editor1=F.J. Ragep |editor2=P. Sally |editor3=S.J. Livesey |year=1996 |title=Tradition, Transmission, Transformation: Proceedings of Two Conferences on Pre-modern Science held at the University of Oklahoma |page=500 |publisher=Brill Publishers |url-status=live |archive-url=https://web.archive.org/web/20160427045853/https://books.google.com/books?id=Kl1COWj9ubAC&pg=PA489 |archive-date=2016-04-27 }} | {{cite journal|author=Nader El-Bizri|title=A Philosophical Perspective on Alhazen's Optics|journal= Arabic Sciences and Philosophy |volume=15 |issue=2|year=2005|pages=189–218|doi=10.1017/S0957423905000172|s2cid=123057532}} | {{cite journal|author=Nader El-Bizri|title=In Defence of the Sovereignty of Philosophy: al-Baghdadi's Critique of Ibn al-Haytham's Geometrisation of Place|doi=10.1017/S0957423907000367|journal=Arabic Sciences and Philosophy |volume=17 |year=2007|pages=57–80|s2cid=170960993}} | {{cite journal|journal=The Medieval History Journal|volume=9|pages=89–98|year=2006|doi=10.1177/097194580500900105|title=The Gaze in Ibn al-Haytham|author=G. Simon|s2cid=170628785}} }}</ref> He rejected the "emission theory" of Ptolemaic optics with its rays being emitted by the eye, and instead put forward the idea that light reflected in all directions in straight lines from all points of the objects being viewed and then entered the eye, although he was unable to correctly explain how the eye captured the rays.<ref>{{cite book |author1=Ian P. Howard |author2=Brian J. Rogers |title=Binocular Vision and Stereopsis |url=https://books.google.com/books?id=I8vqITdETe0C&pg=PA7 |year=1995 |publisher=Oxford University Press |isbn=978-0-19-508476-4 |page=7 |url-status=live |archive-url=https://web.archive.org/web/20160506053650/https://books.google.com/books?id=I8vqITdETe0C&pg=PA7 |archive-date=2016-05-06 }}</ref> Alhazen's work was largely ignored in the Arabic world but it was anonymously translated into Latin around 1200 A.D. and further summarised and expanded on by the Polish monk [[Witelo]]<ref>{{cite book |author1=Elena Agazzi |author2=Enrico Giannetto |author3=Franco Giudice |title=Representing Light Across Arts and Sciences: Theories and Practices |url=https://books.google.com/books?id=ipyT7askd8EC&pg=PA42 |year=2010 |publisher=V&R unipress GmbH |isbn=978-3-89971-735-8 |page=42 |url-status=live |archive-url=https://web.archive.org/web/20160510030553/https://books.google.com/books?id=ipyT7askd8EC&pg=PA42 |archive-date=2016-05-10 }}</ref> making it a standard text on optics in Europe for the next 400 years.<ref>{{cite book | last=El-Bizri | first=Nader | author-link=Nader El-Bizri | chapter=Classical Optics and the Perspectiva Traditions Leading to the Renaissance |  pages=11–30 | editor1-last=Hendrix | editor1-first=John Shannon | editor1-link=John Shannon Hendrix | editor2-last=Carman | editor2-first=Charles H. | title=Renaissance Theories of Vision (Visual Culture in Early Modernity) | date=2010 | location=Farnham, Surrey | publisher=[[Ashgate Publishing]] | isbn=978-1-4094-0024-0}}; {{cite book | last=El-Bizri | first=Nader | author-link=Nader El-Bizri | chapter=Seeing Reality in Perspective: 'The Art of Optics' and the 'Science of Painting' | title=The Art of Science: From Perspective Drawing to Quantum Randomness | editor1-first=Rossella | editor1-last=Lupacchini | editor2-first=Annarita | editor2-last=Angelini | location=Doredrecht | publisher=Springer | date=2014 | pages=25–47}}</ref>

In the 13th century in medieval Europe, English bishop [[Robert Grosseteste]] wrote on a wide range of scientific topics, and discussed light from four different perspectives: an [[epistemology]] of light, a [[metaphysics]] or [[cosmogony]] of light, an [[etiology]] or physics of light, and a [[theology]] of light,<ref>D.C. Lindberg, ''Theories of Vision from al-Kindi to Kepler'', (Chicago: Univ. of Chicago Pr., 1976), pp. 94–99.</ref> basing it on the works of Aristotle and Platonism. Grosseteste's most famous disciple, [[Roger Bacon]], wrote works citing a wide range of recently translated optical and philosophical works, including those of Alhazen, Aristotle, [[Avicenna]], [[Averroes]], Euclid, al-Kindi, Ptolemy, Tideus, and [[Constantine the African]]. Bacon was able to use parts of glass spheres as [[magnifying glass]]es to demonstrate that light reflects from objects rather than being released from them.

The first wearable eyeglasses were invented in Italy around 1286.<ref>{{cite book |last= Ilardi |first= Vincent |date= 2007 |title= Renaissance Vision from Spectacles to Telescopes |location= Philadelphia |publisher= American Philosophical Society |isbn= 978-0-87169-259-7 |pages= 4–5 |url= https://archive.org/details/bub_gb_peIL7hVQUmwC}}</ref>
This was the start of the optical industry of grinding and polishing lenses for these "spectacles", first in Venice and Florence in the thirteenth century,<ref>[http://galileo.rice.edu/sci/instruments/telescope.html "The Galileo Project > Science > The Telescope" by Al Van Helden] {{webarchive|url=https://web.archive.org/web/20120320091537/http://galileo.rice.edu/sci/instruments/telescope.html |date=2012-03-20 }}. Galileo.rice.edu. Retrieved 2012-06-10.</ref> and later in the spectacle making centres in both the Netherlands and Germany.<ref>{{cite book |author=Henry C. King |title=The History of the Telescope |url=https://books.google.com/books?id=KAWwzHlDVksC&pg=PR1 |year=2003 |publisher=Courier Dover Publications |isbn=978-0-486-43265-6 |page=27 |url-status=live |archive-url=https://web.archive.org/web/20160617095507/https://books.google.com/books?id=KAWwzHlDVksC&pg=PR1 |archive-date=2016-06-17 }}</ref> Spectacle makers created improved types of lenses for the correction of vision based more on empirical knowledge gained from observing the effects of the lenses rather than using the rudimentary optical theory of the day (theory which for the most part could not even adequately explain how spectacles worked).<ref>{{cite book |author1=Paul S. Agutter |author2=Denys N. Wheatley |title=Thinking about Life: The History and Philosophy of Biology and Other Sciences |url=https://books.google.com/books?id=Gm4bqeBMR8cC&pg=PA17 |year=2008 |publisher=Springer |isbn=978-1-4020-8865-0 |page=17 |url-status=live |archive-url=https://web.archive.org/web/20160516134901/https://books.google.com/books?id=Gm4bqeBMR8cC&pg=PA17 |archive-date=2016-05-16 }}</ref>{{sfnp|Ilardi|2007|p=[https://archive.org/details/bub_gb_peIL7hVQUmwC/page/n221 210]}} This practical development, mastery, and experimentation with lenses led directly to the invention of the compound [[optical microscope]] around 1595, and the [[refracting telescope]] in 1608, both of which appeared in the spectacle making centres in the Netherlands.<ref>[http://nobelprize.org/educational_games/physics/microscopes/timeline/index.html Microscopes: Time Line] {{webarchive|url=https://web.archive.org/web/20100109122901/http://nobelprize.org/educational_games/physics/microscopes/timeline/index.html |date=2010-01-09 }}, Nobel Foundation. Retrieved April 3, 2009</ref><ref name="LZZginzib4C page 55">{{cite book |first=Fred |last=Watson |title=Stargazer: The Life and Times of the Telescope |url=https://books.google.com/books?id=2LZZginzib4C&pg=PA55 |year=2007 |publisher=Allen & Unwin |isbn=978-1-74175-383-7 |page=55 |url-status=live |archive-url=https://web.archive.org/web/20160508185423/https://books.google.com/books?id=2LZZginzib4C&pg=PA55 |archive-date=2016-05-08 }}</ref>
[[File:Kepler - Ad Vitellionem paralipomena quibus astronomiae pars optica traditur, 1604 - 158093 F.jpg|thumb|left|The first treatise about optics by [[Johannes Kepler]], {{lang|la|Ad Vitellionem paralipomena quibus astronomiae pars optica traditur}} (1604), generally recognized as the foundation of modern optics.<ref>{{cite book |last= Caspar |first= Max |date= 1993 |orig-date= First published 1959 |title= Kepler |publisher= Dover Publications |isbn= 0-486-67605-6 |pages= 142–146 |url= https://archive.org/details/kepler00casp/ |url-access= registration}}</ref>]]

[[File:Opticks.jpg|thumb|right|upright|Cover of the first edition of Newton's ''Opticks'' (1704)]]
[[File:Table of Opticks, Cyclopaedia, Volume 2.jpg|thumb|upright|Board with optical devices, 1728 Cyclopaedia]]
In the early 17th century, [[Johannes Kepler]] expanded on geometric optics in his writings, covering lenses, reflection by flat and curved mirrors, the principles of [[pinhole camera]]s, inverse-square law governing the intensity of light, and the optical explanations of astronomical phenomena such as [[Lunar eclipse|lunar]] and [[solar eclipse]]s and astronomical [[parallax]]. He was also able to correctly deduce the role of the [[retina]] as the actual organ that recorded images, finally being able to scientifically quantify the effects of different types of lenses that spectacle makers had been observing over the previous 300 years.{{sfnp|Ilardi|2007|p= [https://archive.org/details/bub_gb_peIL7hVQUmwC/page/n255 244]}} After the invention of the telescope, Kepler set out the theoretical basis on how they worked and described an improved version, known as the ''[[Keplerian telescope]]'', using two convex lenses to produce higher magnification.{{sfnp|Caspar|1993|pp= [https://archive.org/details/kepler00casp/page/192/mode/2up 192–202]}}

Optical theory progressed in the mid-17th century with [[The World (Descartes)#Cartesian theory on light|treatises]] written by philosopher [[René Descartes]], which explained a variety of optical phenomena including reflection and refraction by assuming that light was emitted by objects which produced it.<ref name=Sabra>{{cite book|title=Theories of light, from Descartes to Newton|author=A.I. Sabra|publisher=CUP Archive|year=1981|isbn=978-0-521-28436-3}}</ref> This differed substantively from the ancient Greek emission theory. In the late 1660s and early 1670s, [[Isaac Newton]] expanded Descartes's ideas into a [[corpuscle theory of light]], famously determining that white light was a mix of colours that can be separated into its component parts with a [[Prism (optics)|prism]]. In 1690, [[Christiaan Huygens]] proposed a wave theory for light based on suggestions that had been made by [[Robert Hooke]] in 1664. Hooke himself publicly criticised Newton's theories of light and the feud between the two lasted until Hooke's death. In 1704, Newton published ''[[Opticks]]'' and, at the time, partly because of his success in other areas of physics, he was generally considered to be the victor in the debate over the nature of light.<ref name=Sabra />

Newtonian optics was generally accepted until the early 19th century when [[Thomas Young (scientist)|Thomas Young]] and [[Augustin-Jean Fresnel]] conducted experiments on the [[Interference (wave propagation)|interference]] of light that firmly established light's wave nature. Young's famous [[Young's interference experiment|double slit experiment]] showed that light followed the [[superposition principle]], which is a wave-like property not predicted by Newton's corpuscle theory. This work led to a theory of diffraction for light and opened an entire area of study in physical optics.<ref>{{cite book|author=W.F. Magie|title=A Source Book in Physics|url=https://archive.org/details/in.ernet.dli.2015.449479|publisher=Harvard University Press|year=1935|page=[https://archive.org/details/in.ernet.dli.2015.449479/page/n323 309]}}</ref> Wave optics was successfully unified with [[electromagnetic theory]] by [[James Clerk Maxwell]] in the 1860s.<ref>{{cite journal|author=J.C. Maxwell|title=A Dynamical Theory of the Electromagnetic Field|journal=Philosophical Transactions of the Royal Society of London|volume=155|pages=459–512|year=1865|bibcode = 1865RSPT..155..459M|doi=10.1098/rstl.1865.0008|title-link=A Dynamical Theory of the Electromagnetic Field|s2cid=186207827}}</ref>

The next development in optical theory came in 1899 when [[Max Planck]] correctly modelled [[blackbody radiation]] by assuming that the exchange of energy between light and matter only occurred in discrete amounts he called ''quanta''.<ref>For a solid approach to the complexity of Planck's intellectual motivations for the quantum, for his reluctant acceptance of its implications, see H. Kragh, [http://physicsworld.com/cws/article/print/373 Max Planck: the reluctant revolutionary] {{Webarchive|url=https://web.archive.org/web/20120401221617/http://physicsworld.com/cws/article/print/373 |date=2012-04-01 }}, ''Physics World''. December 2000.</ref> In 1905, [[Albert Einstein]] published the theory of the [[photoelectric effect]] that firmly established the quantization of light itself.<ref>{{cite book |last1=Einstein |first1=A. |author-link1=Albert Einstein |editor1-first=D. |editor1-last=Ter Haar |title=The Old Quantum Theory |url=https://archive.org/details/oldquantumtheory0000haar |url-access=registration |year=1967 |publisher=Pergamon |pages=[https://archive.org/details/oldquantumtheory0000haar/page/91 91–107] |chapter=On a heuristic viewpoint concerning the production and transformation of light |oclc=534625}} The chapter is an English translation of Einstein's 1905 paper on the photoelectric effect.</ref><ref name=AnnPhysik322132>{{Cite journal |first=A. |last=Einstein |year=1905 |title=Über einen die Erzeugung und Verwandlung des Lichtes betreffenden heuristischen Gesichtspunkt |language=de |trans-title=On a heuristic viewpoint concerning the production and transformation of light |journal=Annalen der Physik |volume=322 |issue=6 |pages=132–148 |doi=10.1002/andp.19053220607|bibcode = 1905AnP...322..132E|doi-access=free }}</ref> In 1913, [[Niels Bohr]] showed that atoms could only emit discrete amounts of energy, thus explaining the discrete lines seen in [[emission spectrum|emission]] and [[absorption spectrum|absorption spectra]].<ref>{{cite journal|url=http://dbhs.wvusd.k12.ca.us/webdocs/Chem-History/Bohr/Bohr-1913a.html |year=1913 |title=On the Constitution of Atoms and Molecules |journal=Philosophical Magazine |volume=26, Series 6 |pages=1–25 |url-status=dead |archive-url=https://web.archive.org/web/20070704225134/http://dbhs.wvusd.k12.ca.us/webdocs/Chem-History/Bohr/Bohr-1913a.html |archive-date=July 4, 2007 }}. The landmark paper laying the [[Bohr model of the atom]] and [[molecular bond]]ing.</ref> The understanding of the interaction between light and matter that followed from these developments not only formed the basis of quantum optics but also was crucial for the [[history of quantum mechanics|development]] of quantum mechanics as a whole. The ultimate culmination, the theory of [[quantum electrodynamics]], explains all optics and electromagnetic processes in general as the result of the exchange of real and [[virtual particles|virtual]] photons.<ref>{{cite book|author=R. Feynman|author-link=Richard Feynman|year=1985|title=QED: The Strange Theory of Light and Matter|chapter=Chapter 1|page=6|publisher=Princeton University Press|isbn=978-0-691-08388-9}}</ref> Quantum optics gained practical importance with the inventions of the [[maser]] in 1953 and of the laser in 1960.<ref>{{cite book|author=N. Taylor|title=LASER: The inventor, the Nobel laureate, and the thirty-year patent war|year=2000|publisher=Simon & Schuster|location=New York|isbn=978-0-684-83515-0}}</ref>

Following the work of [[Paul Dirac]] in [[quantum field theory]], [[George Sudarshan]], [[Roy J. Glauber]], and [[Leonard Mandel]] applied quantum theory to the electromagnetic field in the 1950s and 1960s to gain a more detailed understanding of photodetection and the [[statistical mechanics|statistics]] of light.