Self-action of a light beam in a photorefractive crystal in an alternating electric field upon synchronous intensity modulation

The propagation of a light beam in a photorefractive crystal in an alternating meander electric field is studied. A nonlinear equation is obtained for a spatial charge field formed in the crystal upon modulation of the light intensity synchronously with the applied electric field. It is established theoretically that the spatial charge field has two components, which make contributions to different mechanisms of a photoresponse providing self-focusing and the appearance of spatial solitons, as well as the trajectory self-bending. The conditions are found at which the soliton regime is realised and parameters affecting this regime in a greater extent are determined.