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Doppler Limit

Author: the photonics expert (RP)

Definition: a limit for the temperature which is achievable with certain laser cooling techniques

Category: article belongs to category quantum optics quantum optics

Page views in 12 months: 839

DOI: 10.61835/rda   Cite the article: BibTex plain textHTML   Link to this page!   LinkedIn

The temperature achievable with Doppler cooling, a type of laser cooling, is given by the Doppler limit:

$${T_{\rm{D}}} = \frac{{\hbar \gamma }}{{2{k_{\rm{B}}}}}$$

where ($\gamma$) is the inverse upper-state lifetime, related to the natural linewidth of the atomic transition, and ($k_\textrm{B}$) is the Boltzmann constant. Typical values for the Doppler limit are of the order of hundreds of microkelvins.

Temperatures below the Doppler limit can be reached, e.g. with Sisyphus cooling or with velocity-selective coherent population trapping. It is then possible to reach the lower recoil limit, or even lower temperatures.

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