Coherent effects in the propagation of ultrashort light pulses in resonant media. Part II (Review)

This part of the review deals with coherent effects in the interaction of ultrashort light pulses with media characterized by degenerate transitions, including semiconducting media (in the direct band-band transition region), and with media exhibiting two-photon resonances. It is shown that the self-induced transparency can appear under such conditions and the properties of this effect are studied. A review is made of experimental investigations of the coherent bleaching of various media. The paper ends with a list of the most urgent problems requiring clarification.