Scattering of light by an intense saturating puise in a resonance medium

A linear response of a resonant medium to a weak electromagnetic field is studied in the case when a medium is a gas of three-level atoms subjected to a strong saturating pulse. A noncoherent intense pulse and a coherent 2π pulse (of the kind encountered in the theory of self-induced transparency) are considered. The expressions obtained are used to study the problem of the spectrum of the reflection of light by a pulse moving in a medium. An analysis is made of the possibility of using the Doppler effect, which occurs when light is reflected by a moving pulse, in an investigation of the characteristics of pulse propagation, determination of its parameters, and study of the nonlinear characteristics of the medium itself. Possibilities of experimental observation of the predicted effects are discussed, particularly the possibility of conversion of an electromagnetic radiation spectrum.