Photorefractive self-trapping and deflection of optical beams

Abstract
The band transport model is used to derive the space-charge field induced by an optical beam propagating in photorefractive materials with the application of an external dc field in the steady state. The derivation explicitly displays the screening and diffusion fields and other higher-order corrections to them. The condition caused by the screening field for steady-state self-trapping of the optical beam is found analytically by means of a variational approach and compared with the numerical solution. The deflection of the optical beam that is caused by the asymmetric diffusion field, as well as its effect on self-trapping, are also studied.