Formation of Intensive Pulses with Super Short Duration Under the Cascading SHG in Bulk Medium

Using computer simulation, we investigate cascading SHG under the conditions of action of cubic nonlinearity and group velocity mismatching with the aim of high intense formation of fundamental and doubling frequency waves. The phase mismatching in our computer experiments corresponds to self-focusing of laser pulses. Various scenario of laser pulse formation on doubling frequency with intensity, that is comparable with the one of fundamental harmonic, are found. It should be emphasized under some conditions the centers of both pulses do not change their positions despite on group velocity mismatching and both pulses propagate as in the case of absent of group velocity mismatching. We take into account dispersion and diffraction of laser pulses as well