256X256 LIQUID-CRYSTAL-ON-SILICON SPATIAL LIGHT-MODULATOR

A 256 x 256 pixel spatial light modulator (SLM) is designed and constructed by the use of liquid-crystal-on-silicon technology. The device is a binary electrically addressed SLM with a measured zero-order contrast ratio of 70:1 and an imaged contrast ratio of 10:1. The pixel pitch is 21.6 mum, which gives an array size of 5.53 mm. The electronic load time is 43 mus, and the 10%-90% switching time of the liquid crystal is approximately 75-80 ps at room temperature, which implies a maximum frame rate of approximately 8.3 kHz. We discuss the design trade-offs that are intrinsic to this type of device and describe how the primary application for the device in an optical correlator influenced the final design.