TIME-DEPENDENT EVOLUTION OF AN OPTICAL VORTEX IN PHOTOREFRACTIVE MEDIA

We study the transient decay and rotation of a singly charged optical vortex in media with a photorefractive nonlinearity under conditions w here the light intensity is high compared to the saturation intensity. Transient decay of an initially circular vortex is characterized by c harge-dependent rotation, and stretching of the vortex along the direc tion of the photogalvanic or externally applied field. When the medium reaches a steady state the effective nonlinearity at large times disa ppears and the vortex returns to its initial shape.