Propagation dynamics of high-power femtosecond pulses in Raman-active media

Abstract

We analyze the dynamics of a high-power ultrashort optical pulse in a Raman-active medium in the case when the pulse width is small in comparison with the time a-', where till = E2 - El is the energy difference of levels participating in Raman scattering. The feasibility of new nonlinear effects is shown: the existence of 2m-pulses of self-induced transparency of a Raman-active medium, generation of videopulses of electromagnetic field without carrier frequency starting from a high-frequency signal. We show that under certain conditions the pulse propagation may be accompanied by its temporal compression and at sufficiently high powers by spectrum superbroadening as well. Attention is paid to qualitatively new physics of the processes when the field dynamics is determined by the variation of the photon energy rather than the variation of the photon number.