Recoil, cooling limit effect

Surprisingly, however, we found that the major limitation to our experimental accuracy was due to the recoil imparted by photons to atoms. The radiation forces are of course well-known, being used for laser cooling, nevertheless their effect in precision spectroscopy is often disregarded as the interaction time be-... 

The two methods of demonstrative character considered above should be supplemented with the classical Doppler-cooling method for forbidden transitions with a very small radiative broadening 7. In the first experiments of this kind (Katori et al. 1999) with an ensemble of Sr atoms, a 3D-cooling temperature that was close to a single effective recoil was obtained, that is, the alternative cooling pathway shown on the left of Fig. 5.4 was realized. Moreover, in the case of polychromatic excitation, there is even a possibility of reaching a temperature below the recoil limit (Wallis and Ertmer 1989). 

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