Stimulated Raman scattering in resonant nonequilibrium media

An analysis is made of the propagation of a short coherent optical pulse in a three-level resonant medium with an essentially nonequidistant spectrum as a function of the degree of preexcitation of the medium. It is found that in addition to self-induced transparency and resonance scattering, stimulated Raman scattering (Stokes or anti-Stokes) should be observed under certain spatial phase-matching conditions. The area theorem is formulated for all radiation components. An analysis is made of the case of propagation of a resonant electromagnetic pulse of frequency $\omega$ in a system of three-level atoms having an equidistant spectrum. Under conditions of preexcitation of the medium at the frequency $2\omega$ by longitudinal acoustic pulses, a scattered transverse acoustic wave at the frequency $\omega$ may be observed.