1D beam self-trapping in a SBN crystal

Self-trapping in photorefractive materials is one of the most investigated effects during the past decade. Usually one utilizes the Pockel’s effect in photorefractive crystals, whereas the natural divergence of the beam is compensated by non-linear focusing. The effect depends on beam intensity and polarization, applied electric field, background illumination, crystal geometry and material properties. In this work we present experimental and numerical investigations of the self-trapping effect in a SBN crystal (5mm x 5mm x 20mm) for different beam intensities, applied electric fields, and background illuminations. Based on the obtained state diagrams we received stable solitons with prescribed properties. Also the self-bending effect was shown experimentally. A (1+1)-dimensional model of beam propagation was studied numerically using the Douglas scheme for Gaussian input beams. We show how self-focusing and self-bending depend on the external electrical field, intensity and waist of the input beam. Furthermore, the time for soliton formation was calculated numerically.