PROPAGATION OF LIGHT IN A J=1/2]-]J'=1/2 RESONANT MEDIUM

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.