ULTRABROADBAND ACTIVE MEDIA FOR GENERATION OF ULTRASHORT OPTICAL PULSES

Two methods for realizing ultrabroadband active media for the direct g eneration of extremely short pulses in lasers are analyzed. The main p eculiarities of the first method of ultrashort pulses generation in th e lasers with composite active medium, consisting of several active me dia with overlapping gain bands, have been investigated. It has been s hown that, under certain conditions, in this laser, the stationary reg ime in the form of ultrashort pulses generation with duration determin ated by combined gain bandwidth, may be realized. In the second case, our investigations demonstrate that Jahn-Teller ions in acentrical pos itions of oxide crystals, due to removing the degeneracy of orbital de generate excited and ground states, can have anomalous wide bands of l uminescence. Such laser media are promising for the generation of femt osecond optical pulses.