Self-bending specklons in photorefractive crystals

Abstract
The nonlinear problem of speckle-beam propagation in a photorefractive crystal with a strong diffusion-grating response has been solved. The approximate self-sustaining solution has been found that conserves the Gaussian shape of an angular spectrum of the beam but gradually tilts its propagation direction. The rate of angular tilting is proportional to the square of the beam’s angular divergence and depends on the crystal-axis orientation.