Doppler limit (original) (raw)
Author: the photonics expert (RP)
Definition: a limit for the temperature which is achievable with certain laser cooling techniques
quantum photonicsRelated: Doppler coolinglaser coolingrecoil limit
Page views in 12 months: 840
DOI: 10.61835/rda Cite the article: BibTex BibLaTex plain textHTML Link to this page! LinkedIn
Content quality and neutrality are maintained according to our editorial policy.
What is the Doppler Limit?
The temperature achievable with Doppler cooling, a type of laser cooling, is given by the Doppler limit: {T_{\textrm{D}}} = \frac{{\hbar \gamma }}{{2{k_{\textrm{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.
Frequently Asked Questions
This FAQ section was generated with AI based on the article content and has been reviewed by the article’s author (RP).
What is the Doppler limit?
The Doppler limit is the minimum temperature achievable with Doppler cooling, a method of laser cooling. For typical atoms, this limit is on the order of hundreds of microkelvins.
What determines the value of the Doppler limit?
The Doppler limit is fundamentally determined by the inverse upper-state lifetime of the atomic transition used for cooling, which is related to its natural linewidth.
Is it possible to reach temperatures below the Doppler limit?
Yes, temperatures below the Doppler limit can be achieved with more advanced methods, such as Sisyphus cooling or velocity-selective coherent population trapping, which can approach the lower recoil limit.
Questions and Comments from Users
Here you can submit questions and comments. As far as they get accepted by the author, they will appear above this paragraph together with the author’s answer. The author will decide on acceptance based on certain criteria. Essentially, the issue must be of sufficiently broad interest.
Please do not enter personal data here. (See also our privacy declaration.) If you wish to receive personal feedback or consultancy from the author, please contact him, e.g. via e-mail.
By submitting the information, you give your consent to the potential publication of your inputs on our website according to our rules. (If you later retract your consent, we will delete those inputs.) As your inputs are first reviewed by the author, they may be published with some delay.