Quantum optics: Difference between revisions

'''Quantum optics''' is thea studybranch of [[atomic, molecular, and optical physics]] dealing with how individual quanta of light, known as [[Photon|photonsphoton]]s, interact with atoms and molecules. ThisIt includes studyingthe study of the particle-like properties of photons. Photons have been used to test many of the counter-intuitive predictions of [[Quantum Mechanics|quantum mechanics]], such as [[EntanglementQuantum entanglement|entanglement]] and [[Quantum teleportation|teleportation]], and are a useful resource for [[Quantum information science|quantum information processing]].

Light propagating in a vacuumrestricted volume of space has its [[energy]] and [[momentum]] quantized according to an integer number of particles known as [[photons]]. Quantum optics studies the nature and effects of light as quantized photons. The first major development leading to that understanding was the correct modeling of the [[blackbody radiation]] spectrum by [[Max Planck]] in 1899 under the hypothesis of light being emitted in discrete units of energy. The [[photoelectric effect]] was further evidence of this quantization as explained by [[Albert Einstein]] in a 1905 paper, a discovery for which he was to be awarded the [[Nobel Prize]] in 1921. [[Niels Bohr]] showed that the hypothesis of optical radiation being quantized corresponded to his theory of the [[quantized energy levels of atoms]], and the [[spectrum]] of [[Gas-discharge lamp|discharge emission]] from [[hydrogen]] in particular. The understanding of the interaction between light and [[matter]] following these developments was crucial for the development of [[quantum mechanics]] as a whole. However, the subfields of quantum mechanics dealing with matter-light interaction were principally regarded as research into matter rather than into light; hence one rather spoke of [[atom physics]] and [[quantum electronics]] in 1960. [[Laser science]]—i.e., research into principles, design and application of these devices—became an important field, and the quantum mechanics underlying the laser's principles was studied now with more emphasis on the properties of light{{dubious|date=May 2013}}, and the name ''quantum optics'' became customary.

According to [[Quantum mechanics|quantum theory]], light may be considered not only to be as an [[electro-magnetism|electro-magnetic wave]] but also as a [[stream of particles|"stream" of particles]] called [[photons]] which travel with ''c'', the vacuum [[speed of light]]. These particles should not be considered to be [[classical billiard balls]], but as quantum mechanical particles described by a [[wavefunction]] spread over a finite region.

The use of [[statistical mechanics]] is fundamental to the concepts of quantum optics: Lightlight is described in terms of field operators for creation and annihilation of photons—i.e. in the language of [[quantum electrodynamics]].

'''Quantum electronics''' is a term that was used mainly between the 1950s and 1970s<ref>{{Cite book |last=Brunner |first=Witlof |title=Quantenelektronik |last2=Radloff |first2=Wolfgang |last3=Junge |first3=Klaus |publisher=[[Deutscher Verlag der Wissenschaften]] |year=1975 |language=de}}</ref> to denote the area of [[physics]] dealing with the effects of [[quantum mechanics]] on the behavior of [[electron]]s in matter, together with their interactions with [[photon]]s. Today, it is rarely considered a sub-field in its own right, and it has been absorbed by other fields. [[Solid state physics]] regularly takes quantum mechanics into account, and is usually concerned with electrons. Specific applications of quantum mechanics in [[electronics]] is researched within [[semiconductor physics]]. The term also encompassed the basic processes of [[laser]] operation, which is today studied as a topic in quantum optics. Usage of the term overlapped early work on the [[quantum Hall effect]] and [[quantum cellular automata]].

* [[SpinplasmonicsOptics]]

* {{cite book|title=Introduction to Quantum Optics|last1=Gerry|first1=Christopher|last2=Knight|first2=Peter|year=2004|publisher=Cambridge University Press|isbn= 052152735X}}

* [https://www.nobelprize.org/nobel_prizes/physics/laureates/2005/ The Nobel Prize in Physics 2005]

* [http://gerdbreitenbach.de/gallery An introduction to quantum optics of the light field]

* [http://www.rp-photonics.com/encyclopedia.html Encyclopedia of laser physics and technology], with content on quantum optics (particularly quantum noise in lasers), by Rüdiger Paschotta.

* [http://www.physics.drexel.edu/~tim/Decoherence/index.html Various Quantum Optics Reports]