Fidelity Of Real-Time Correlation By Four-Wave Mixing

In this paper we consider the conditions on relative beam powers and interaction region geometry necessary to obtain accurate correlation of two input images via degenerate four wave mixing in photorefractive materials. We also show how the correlation product may be 'weighted' to improve peak to background discrimination either by appropriately adjusting the beam intensities or by introducing an extra control beam. The discussion is supported both by experimental results and numerical simulations.