Transient processes in propagation of an ultrashort pulse in a three-level medium

An analysis is made of the effects associated with the propagation of an ultrashort pulse in a three-level resonance medium. It is shown that the dynamics of the changes in the pulse during its propagation differs considerably from the usual self-induced transparency effect in a two-level medium. It is predicted theoretically that there should be a propagation regime accompanied by periodic variation of the pulse shape.