Abstract

Binary spatial light modulators have the advantage of better spatial and temporal uniformity than continuous spatial light modulators due to their binary thresholding nature. The multiple level modulators presented herein have a similar uniformity advantage while offering more than a single bit of modulation. Typically, ferroelectric liquid crystal (FLC) spatial light modulators (SLM) are fabricated as halfwave plates using FLC materials which give a 45° rotation of the optic axis between their two switched states. They are used for binary magnitude or binary phase modulation. We present schemes for achieving multiple bits of modulation based on using a halfwave layer of FLC material for each bit of a modulation. The degree of modulation is directly related to the amount of rotation of the optic axis which, in turn, is a property of the specific FLC material used. Therefore successive layers require the use of different FLC materials.

© 1989 Optical Society of America