Coherent Pulse Propagation Effects in Multilevel Molecular Systems

Abstract

Coherent pulse propagation effects in multilevel molecular systems have received much attention experimentally, as is indicated by the experimental literature on self-induced transparency (SIT) and other coherent propagation effects in SF₆ [1–5]. Theoretical studies by HOPF, RHODES and SZOKE [6] and GIBBS, MCCALL and SALAMO [5] based on the methods of HOPF and SCULLY [7] and ICSEVGI and LAMB [8] have been directed towards understanding the influence of spatial (M) degeneracy and Doppler broadening on SIT and other coherent propagation effects. More recent theoretical studies have been concerned with nonlinear-optical effects in multilevel systems [9]; pulse-propagation calculations have been performed for a special case of a three-level system (common ground state) [10]. A basic physical question addressed in these works is, to what extent does the occurrence of different dipole transition moments and Rabi frequencies in a multilevel system cause coherent effects to cancel, perhaps leading to behavior that can be described by rate equations? In this paper we describe a general method for addressing this and related questions in systems which possess many radiatively connected levels (Fig.1), as well as many spatial (M) levels.