Two-Photon Doppler cooling of alkaline-earth-metal and ytterbium atoms

Abstract

A new possibility of laser cooling of alkaline-earth-metal and Ytterbium atoms using a two-photon transition is analyzed. We consider a ${}^1{S}_0$ - ${}^1{S}_0$ transition, with excitation in near resonance with the ${}^1{P}_1$ level. This greatly increases the two-photon transition rate, allowing an effective transfer of momentum. The experimental implementation of this technique is discussed and we show that for Calcium, for example, two-photon cooling can be used to achieve a Doppler limit of 123 microKelvin. The efficiency of this cooling scheme and the main loss mechanisms are analyzed.

7 pages, 5 figures