Physical Review Letters
Measurement of the friction coefficient in 1D corkscrew optical molasses by stimulated Rayleigh spectroscopy
Brahim Lounis, J.-Y. Courtois, Philippe Verkerk, Ch Salomon, G. Grynberg
Abstract
The transmission spectrum of a probe interacting with one-dimensional cesium optical molasses made from two circularly cross-polarized cooling beams (corkscrew molasses) displays a narrow (\ensuremath{\approxeq}30--70 kHz) Rayleigh resonance. From the width of this resonance we deduce the friction coefficient of the cooling force to be \ensuremath{\alpha}=(5.8\ifmmode\pm\else\textpm\fi{}0.4)\ensuremath{\Elzxh}${\mathit{k}}^{2}$ for a detuning from resonance equal to 3\ensuremath{\Gamma}. This value is in quantitative agreement with theoretical predictions. We also show that the shape of the Rayleigh resonance depends dramatically on the efficiency of the sub-Doppler cooling mechanism.