Generation and evolution of quadratic dark spatial solitons using the wavefront modulation method.

We study the evolution of dark spatial solitons by chi((2)): chi((2)) cascaded nonlinearity. The generation and evolution of solitons pairs by the optical branching effect is investigated. It is shown that the number of solitons pairs and the transverse velocity of a given pair depend on the parameters of the input beam. We also investigate the hollows generated in a beam with a uniform background when the two sides of the input beam have various phase difference. It is concluded that dark spatial solitons by chi((2)): chi((2)) cascaded nonlinearity have analog performance compared with that in chi((3)) defocusing Kerr media.