Propagation of an ultrashort light pulse in a three-level laser amplifier

The inverse scattering transform method is used in a study of the evolution of light pulses in an initially inverted three-level medium of the Λ type. An asymptotic solution describing the profile of the first spike is obtained for small-area priming pulses. It is shown that this asymptote is determined entirely by the initial populations of the lower levels and by the profile of the priming pulses. A special case of this problem is the propagation of two-component light in a laser amplifier using the degenerate J = 0–J = 1 transition.