SURFACE-PLASMON SPATIAL LIGHT MODULATORS BASED ON LIQUID-CRYSTAL

The development of a new class of spatial light modulator (SLM), which uses modulation of lossy guided waves generated by surface-plasmon resonance, is described. The potential advantages of this technique are explained, including increased response uniformity and enhanced sensitivity and speed. An optically addressed SLM that is based on a nematic liquid crystal with a spatial resolution better than 10 line pairs/mm (at 50% modulation transfer function) is demonstrated. For the design of devices that are based on newer smectic liquid crystals the use of anisotropy-induced polarization mixing and the so-called pseudoplasmon modes are described. Such modes offer controllable sensitivity-spatial resolution characteristics in simple liquid-crystal SLM structures. Within a typical SLM resolution requirement of 10 line pairs/mm, for example, the sensitivity can be optimized to obtain a theoretical reflectivity modulation from 0 to 0.7 for a liquid-crystal director modulation of 5-degrees.