Abstract

The general features of optical molasses,¹ continuously loaded with slow sodium atoms, are described. Three orthogonal pairs of counterpropagating laser beams, tuned slightly below resonance, capture and viscously confine the slow atoms which are produced continuously by a Zeeman tuned laser-cooled atomic beam.² The continuous loading of this molasses region is further enhanced by using optical depumping techniques (optically pumping the atoms out of the cooling cycle with another laser) to extract more slow atoms from the beam than are otherwise available. Results from simple analytic theories and Monte Carlo simulations of the molasses are compared to the experimental findings. In particular, we look at the molasses lifetime as a function of beam imbalance and laser frequency. Although some features of the molasses can be explained (in particular at low intensity) many discrepancies are noted. One most obvious of these is the relative insensitivity of the lifetime to intensity imbalance, the discrepancy being at least an order of magnitude in added rate.

© 1987 Optical Society of America