Characteristics of reflection of an ultrashort light pulse from a thin layer of a nonlinear medium

A numerical analysis is used to formulate the conditions for the manifestation of bistable reflection of a quasimonochromatic light pulse from a thin layer of a resonant medium with nonlinear refraction. The duration of the light pulse is assumed to be less than the phase relaxation time of the nonlinear material. The nonlinearity is due to the existence, in the energy structure of the active atoms, of transitions adjacent to resonances.