Abstract

The insensitivity of the molasses decay rate to the imbalance ΔI between intensities of counterpropagating molasses beams is one of most serious discrepancies between experimental observations and classical theory predictions.^1,2 According to this theory, an imbalance ε = ΔI/I leads to a drift of atoms along the direction of the stronger beam with the velocity v_drift = εF/β, where F is the force from one beam and Γ is the friction coefficient. For optimal damping conditions, v_drift = εΓ/2k, where Γ is the linewidth of the transition and k is the light wave vector. As a result, a 1% imbalance gives a theoretical drift time of 0.2 s, whereas the experimentally observed drift-induced decay rate is a factor of 10 or 20 times smaller. We propose an explanation of this effect in the framework of the classical two-level atom theory, accounting for the rotational motion of atoms in a misaligned supermolasses device.

© 1995 Optical Society of America