A Review of Spatial Light Modulators

Abstract

Over the past two decades a large variety of electronically and optically addressed devices for impressing information onto one- and two- dimensional optical wavefronts have been proposed.1−16 These spatial light modulators (SLM's) were initially developed for such applications as: 1−5projection and flat-screen display, page composers, laser printing, optical memory, incoherent-to-coherent conversion (e.g., for matched filtering and spectrum analysis), optical wavelength conversion, time-to-space conversion for optical signal processsing, and a reusable substitute for film (e.g., for Fourier-plane convolution /correlation filters, real-time holography, and synthetic aperture radar systems). Limited success in those applications has spurred proposals to employ SLM's in such more advanced contexts as: arithmetic operations (×, +, −, /) between image fields, nonlinear intensity processing (e.g., log, √, thresholding, inversion, A/D conversion), 2-D integrating detection, image-field light-level amplification and regeneration, white light/color image processing, optical feature extraction and pattern recognition (non matched-filtering approaches), edge detection, solution of partial differential equations, Boolean logic (AND, OR, NOR, XOR, etc), high-resolution adaptive optics, optical matrix algebraic computing, associative parallel processing, and optical interconnect. With continued SLM development, powerful general parallel optical computers and information processors can be seen on the horizon, probably targeted toward applications from such areas as robot vision and artificial intelligence.