Progress in the development and applications of optically controlled liquid crystal spatial light modulators (review)

A review is given of recent progress in the development and applications of spatial light modulators (controlled transparencies) in the form of photosensitive multilayer structures containing a liquid crystal. A considerable improvement is reported in the most important parameters of the process of modulation of light such as the sensitivity (now 10^–11 J/cm²), resolution (now 300 mm^–1), and speed of response (hundreds and thousands of frames per second). There has been an expansion in the functional capabilities: the modulators can now handle infrared radiation, identify boundaries of objects and regions with time-dependent illumination in converted images, modulate light at one or several stable transmission levels, etc. Some new applications are described, particularly those in processing of television images and in real-time interferometry.