PHOTOREFRACTIVE SELF-TRAPPING AND DEFLECTION OF OPTICAL BEAMS

The band transport model is used to derive the space-charge field indu ced by an optical beam propagating in photorefractive materials with t he application of an external do field in the steady state. The deriva tion explicitly displays the screening and diffusion fields and other higher-order corrections to them. The condition caused by the screenin g field for steady-state self-trapping of the optical beam is found an alytically by means of a variational approach and compared with the nu merical solution. The deflection of the optical beam that is caused by the asymmetric diffusion field, as well as its effect on self-trappin g, are also studied. (C) 1996 Optical Society of America