Recoil temperature

In laser cooling, the Boltzmann constant times the recoil temperature is equal to the recoil energy deposited in a single atom initially at rest by the spontaneous emission of a single photon.^[1] The recoil temperature is

$T_{{recoil}}={\frac {\hbar ^{2}k^{2}}{2mk_{B}}}$ ,

since the photon's momentum is $p = \hbar k$ (here $k$ is the wavevector of the light, $m$ is the mass of an atom, $k_{B}$ is Boltzmann's constant and $\hbar$ is Planck's constant). The recoil temperature for the D2 lines of alkali atoms is typically on the order of 1 μK, and thus lower than the Doppler temperature.^[2] An example of a process where the recoil temperature can be reached is Sisyphus cooling.^[3]

References

↑ Metcalf and van der Straten (1999). Laser Cooling and Trapping. New York: Springer-Verlag. ISBN 0-387-98728-2.
↑ Cohen-Tannoudji, Claude N. (1 July 1998). "Nobel Lecture: Manipulating atoms with photons". Reviews of Modern Physics. 70 (3): 707–719. Bibcode:1998RvMP...70..707C. doi:10.1103/RevModPhys.70.707.
↑ Cohen-Tannoudji, C. (2004). Atoms in electromagnetic fields (2nd ed.). Singapore: World Scientific. ISBN 978-9812560193.

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