High-speed analog spatial light modulator using a hydrogenated amorphous silicon photosensor and an electroclinic liquid crystal

Abstract

A high-speed optically addressed spatial light modulator is described which uses the electroclinic effect in chiral smectic A liquid crystals with a p-i-n photodiode of hydrogenated amorphous silicon (a-Si:H). The near microsecond response time is a function of the liquid-crystal mixture and temperature. We present and analyze optical modulation measurements of a device which exhibits a response time of 40 μs at 29°C and 4 μs at 50°C. The optical response is continuous and linear with electric field and write-light intensity, allowing for grey level applications.