AN IMPROVED PHOTOREFRACTIVE JOINT-TRANSFORM CORRELATOR UTILIZING BEAM-FANNING IN A HIGH-GAIN BARIUM-TITANATE CRYSTAL

A photorefractive nonlinear joint-transform correlator is demonstrated by utilizing the nonlinear intensity-dependent behavior of beam-fanni ng in a photorefractive barium titanate crystal. The results obtained reveal a narrowing of the correlation profile, and improved peak-to-si de lobe ratio resulting in a better discrimination ability of the corr elator. The compressional beam-fanning nonlinearity is modelled for a simulation study in order to give a comparison with the experimental o bservation.