256 x 256 liquid - crystal - oll - silicon spatiaf l ight modulator Douglas

A spatial light modulator (SLM) is a device that can impress information on an optical wave front. An electrically addressed SLM translates information from the electronic domain to the optical domain. The applications for SLM's are numerous; they inciude coherent optical processing applications, data routing, data input to optical processing systems, and information display. Spatial light modulation can be accomplished by electro-optic, acousto-optic, magneto-optic, mechanical, photorefractive, optical absorption, and interference effects in a variety of materials.l The advantages of liquid-crystal (LC)materials forSLM's include their high birefringence and low-voltage operation. These properties permit large optical effects to be induced in LC layers a few wavelengths thick. The low-power operation of the LC materials permits Iarge arrays to be constructed to operate at gigabit per second data rates, even though the individual pixels switch in the tens of microseconds time scale. The integration of LC's with silicon backplanes has been a primary technolory for research in smart pixel deA256 x 256 pixel spatial light modulator (SLM) is designed and constructed by the use of liquid-crystalon-silicon technolory. 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 pm, which gives an array size of 5.53 mm. The electronic load time is 43 ps, and the 10Vo-90Vo switching time of the liquid crystal is -75-80 ps at room temperature, which implies a maximum frame rate of -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.