Review of coherent optical processing

Abstract

The use of laser light to perform linear and nonlinear computational operations is reviewed. On linear operations, we discuss schemes involving gratings, computer holograms and optical feedback for addition, subtraction, differentiation, generalized orthogonal transformations and feedback operations. The important methods for implementing the spatial filters and for real-time processing are then briefly described. On nonlinear operations, we discuss technique involving ϕ-modulation, half-tone-screen processes, and nonlinear optical elements with and without coherent feedback for logarithm and thresholding operations. The state-of-the-art of optical processing research and its application areas are then considered at the end.