Spontaneous parametric scattering

Spontaneous parametric scattering (SPDC) is an important process in quantum optics in which scattered photons form in the form of entangled pairs, forming the so-called biphoton field . In the SPR process, a nonlinear medium (crystal) divides the incoming photons into pairs whose total energy and momentum are equal to the energy and momentum of the input photons.

The phenomenon predicted in 1966 Klyshko D.N. , explained and studied with co-authors until 1981, awarded the state prize in 1983 .

Appearance Mechanism

One quantum with energy $\hbar \omega _{3}$ ${\ displaystyle \ hbar \ omega _ {3}}$ $\hbar \omega _{3}$ splits into two quanta with energies $\hbar \omega _{1}$ ${\ displaystyle \ hbar \ omega _ {1}}$ $\hbar \omega _{1}$ and $\hbar \omega _{2}$ ${\ displaystyle \ hbar \ omega _ {2}}$ $\hbar \omega _{2}$ subject to the law of conservation of energy $\hbar \omega _{3}=\hbar \omega _{1}+\hbar \omega _{2}$ ${\ displaystyle \ hbar \ omega _ {3} = \ hbar \ omega _ {1} + \ hbar \ omega _ {2}}$ $\hbar \omega _{3}=\hbar \omega _{1}+\hbar \omega _{2}$ and the law of conservation of momentum $\hbar k_{3}=\hbar k_{1}+\hbar k_{2}$ ${\ displaystyle \ hbar k_ {3} = \ hbar k_ {1} + \ hbar k_ {2}}$ $\hbar k_{3}=\hbar k_{1}+\hbar k_{2}$ where $k$ ${\ displaystyle k}$ $k$ is the wave vector of the photon.

Where used

The generated frequencies are determined by the law of conservation of momentum, i.e. direction in the crystal in which this law holds for given frequencies. Thus, by rotating the crystal, it is possible to smoothly change the frequency of the generated radiation over a wide range. This phenomenon is used to generate frequency - tunable infrared radiation .

Literature

Klyshko D.N., Penin A.N., Polkovnikov B.F., Parametric luminescence and light scattering by polaritons, JETP Letters, Volume 11, pp. 11-14 (1970) .
Delone N.B. The interaction of laser radiation with matter. Lecture course, M., Science, 1989, 280 p.
Voronov V.K., Podoplelov A.V. Modern Physics: Textbook. - M .: KomKniga, 2005, 512 pp., ISBN 5-484-00058-0 , ch. 1 Nonlinear optics, n 1.1 Multiphoton processes.

Spontaneous parametric scattering

Appearance Mechanism

Where used

Literature

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