Abstract

Spatial light modulators with a range of 2π phase modulation, high diffraction efficiency, and video frame rate operation are now becoming available. Innaccurate set ting of the phase at each pixel can arise from several sources, e.g., thermal noise on SLM control signals, quantization of signal levels, and non-identical response of pixels to signals. Random phase errors reduce the intensity of desired diffraction patterns and increase the diffuse background of speckle, thus reducing contrast. We present analytic expressions for the average intensity and variance of the angular spectrum of phase-only transmittance. Errors in position and tilt of each pixel are treated as independent and identically distributed random variables. These assumptions are general enough to describe most deformable mirror modulators and other phase-only SLMs in conditions that can be achieved in the laboratory. We present a specific simulation showing the effects of phase errors on phase-only correlation. The number of operations used to calculate the expectations is on the same order of magnitude as that required for the deterministic calculation of diffraction patterns.

© 1992 Optical Society of America