PROPAGATION OF AN OPTICAL BEAM IN A PHOTOREFRACTIVE MEDIUM IN THE PRESENCE OF A PHOTOGALVANIC NONLINEARITY OR AN EXTERNALLY APPLIED ELECTRIC-FIELD

We consider propagation of a light beam in photorefractive media in the framework of a three-dimensional model. We formulate equations governing three-dimensional distribution of a nonlinear refractive index. The distributions of electric charge, potential, current, refractive index, and the near- and far-field output intensities of the beam are calculated. The conditions necessary for observing self-focusing in photorefractive media are discussed. © 1995 The American Physical Society.