Atomic Relaxation in the Presence of a Coherent Optical Field

Abstract

Atomic relaxation in the presence of a strong coherent optical field is examined. Contrary to popular practice, we find that the Bloch equations do not apply when the applied field is strong enough to saturate the transition. The component of the induced polarization in phase with the field lives longer than the out-of-phase component. One important consequence is that pulse durations for adiabatic inversion of atomic levels need not be short relative to the transverse relaxation time of the atom if the pulse amplitude is sufficiently large.