Interaction of Spatial Solitons in a Saturable Photorefractive Medium

Abstract

Chapter 4 is dedicated to the physics of soliton formation in a photorefractive material and shows that the nonlinear formation of a space charge field due to the incident light beam can be balanced by screening an externally applied electric field, thus leading to a self-guided, stable beam. From a mathematical as well as a physical point of view, this solitary wave is very similar to spatial solitons in saturable media. The anisotropy of the photorefractive effect due to the application of the external electric field leads to an asymmetry of the refractive index created by the beams that strongly influences the formation of spatial photorefractive solitons. The most peculiar features are elliptically shaped solitary solutions, beam bending and diameter oscillations during soliton formation.