Abstract

Imperfections in today's spatial light modulators (SLMs) include one or more of the following: inactive zones in modulators with spatially discrete pixels, mixed (phase/amplitude) modulation rather than pure phase or pure amplitude modulation, nonlinear transfer characteristics in both optically and electrically addressed SLMs, bandpass spatial frequency characteristics in some devices, and strong readout light absorption losses in certain devices. When SLMs are used in optical processors, these imperfections lead to a variety of problems, including loss of correlation peak sharpness in optical processors, image distortion and blurring, fixed pattern noise in reconstructed images, and low signal throughput in complex systems. Continuous-pixel SLMs with spatially continuous drivers offer sufficient spatial resolution to solve the inactive zone problem. While phase-only and almost-amplitude-only modulators exist, there seems to be no device that offers a linear relationship between modulator output (modulated readout light amplitude or phase) and driver characteristic (e.g., write light intensity or electrode voltage) over the full modulation range of the device. Application-specific modulator choice is therefore an important consideration.

© 1992 Optical Society of America