Optical spatial shock waves in photorefractive media

Summary form only given. Shock waves have been extensively investigated in diverse areas of physics. However, their occurrence in optics is rather rare and thus far no such optical structures have been experimentally observed. In this paper we report a new family of kink-antikink shock waves that is possible in unbiased photorefactive media via the two wave mixing process. These waves move together as locked states, and have the interesting property of moving outside their initial /spl plusmn//spl theta/ sector of propagation. The apparent direction of propagation and the spatial widths of these shock wave beams are directly related to their relative intensity. We provide a detailed analysis of these waves, and we illustrate their behavior with pertinent examples.