Dynamic photorefractive Schlieren system.

We present a dynamic Schlieren system that uses optical phase conjugation in a photorefractive crystal. The theoretical description of the system predicts that the square of the phase change in an object field is mapped as the intensity modulation in the system output. This is demonstrated experimentally with a He-Cd laser and a BaTiO(3) crystal arranged in the self-pumped phase-conjugator configuration.