PHOTOREFRACTIVE TIME-INTEGRATING CORRELATOR

We propose and demonstrate a new configuration of a photorefractive time-integrating correlator system using acousto-optic devices to process rf signals. In our system, two rf signals are transferred onto two laser beams by two acousto-optic devices, and the beams interact inside a photorefractive crystal to form a grating for time integration and correlation. The novelty of our scheme is that the direction of the rf signal in the beams is orthogonal to the resulting grating wave vector inside the crystal. This new geometry eliminates any resolution-limiting cross talk that arises from undesirable beam interactions. It also permits a longer crystal interaction length, which reduces constraints on the photorefractive material.