Theory of three-wave acoustooptic interaction

The nonstationary pulse regimes present during nonlinear acoustooptic interaction between two collinear electromagnetic waves and sound are studied analytically and numerically. The feasibility of forming envelope solitons from boundary perturbations (signals) is demonstrated. In the case of pumping at the highest frequency, soliton-like regimes can be formed from the small perturbations which result from convective instability. If the pumping frequency is intermediate, than the solitons form only at a superthreshold amplitude of the boundary signal. An interpretation of soliton velocity based on Whitham relations is given.