Role of the local response of a photorefractive medium in the formation of a spatial screened soliton

The propagation of intensity-modulated laser radiation in a barium — sodium niobate crystal is studied in an external electric field. The possibility of controlling a nonlinear local response of the crystal is demonstrated. It is shown experimentally that the conditions of formation of a one-dimensional spatial soliton can be changed by varying the nonlinear response of the crystal.