SPECIFIC SUB-DOPPLER RESONANCE OF THIN CE LLS

We report on the observation of sub-Doppler features in the transmissi on spectrum of very thin resonant cells. They are related with a trans ient regime of optical pumping, which maximizes the contribution of at oms with small normal velocities. Extension to polarization spectrosco py is demonstrated, and should provide a new compact spectroscopic too l, only requiring very low laser power and atomic density.