Image amplification by two-wave mixing in photorefractive crystals.

Coherent amplification of images by two-wave mixing in photorefractive crystals is examined with attention given to processing in the Fourier domain. It is shown that the gain that is experienced as the probe image traverses the crystal is approximately uniform across the image. The gain can be expressed as a function of the average probe to pump intensity ratio. Experimental verification is given to support the theory.