Propagation of a self-induced transparency pulse in a spatially dispersive medium

Propagation of a self-induced transparency pulse in spatially dispersive media is analyzed. A generalized model of two-level systems allowing for excitonic energy transfer is proposed. Periodic and soliton solutions to the governing equations are found. Estimates show that the spatial dispersion of a pulse propagating in a slow-light medium can be substantially enhanced and become important in the case of resonant transition and sufficiently long pulse duration.