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 where the light intensity is high compared to the saturation intensity. Transient decay of an initially circular vortex is characterized by charge-dependent rotation, and stretching of the vortex along the direction of the photogalvanic or externally applied field. When the medium reaches a steady state the effective nonlinearity at large times disappears and the vortex returns to its initial shape.