Spatial modulation of light in photosensitive high-resolution metal–insulator–semiconductor structures with liquid crystals

An investigation was made of spatial light modulators utilizing the electrooptic effects in a liquid-crystal layer, acting as the insulator in a photosensitive metal–insulator–semiconductor structure. The semiconductor was a crystal of bismuth silicate or germanate. A high value of the energy sensitivity, up to 2 cm${}^2$/$\mu J$ (for total modulation of light), was obtained; the intensity of the control (switching) light in the blue part of the spectrum was 25-30$\mu W$/cm${}^2$. The resolution was up to 200 lines/mm (deduced from the fall to half the maximum value of the frequency-contrast characteristic). The liquid crystals employed made it possible to reach a frame repetition frequency of 30-50 sec${}^{-1}$ at room temperature. A two-frequency supply of the modulator structure made it possible to achieve a controlled memory regime with a data storage time up to 2 sec, and with recording and erasure times of $\thicksim1$ msec.