Propagation of light in a J=1/2<-->J'=1/2 resonant medium

Abstract

The propagation of light in a resonant medium with multiple sublevels depends on the populations of and coherences between theses sublevels. We analyze the case of a J=1/2<-->J'=1/2 transition with arbitrary ground-state polarization in the limit of a weak probe beam. It is found that transverse components of the ground-state orientation lead to a longitudinal component in the eigenpolarizations; a laser beam propagating through an optically pumped medium should therefore be displaced laterally.