ANALOG OPTICAL-PHASE MODULATOR BASED ON CHIRAL SMECTIC AND POLYMER CHOLESTERIC LIQUID-CRYSTALS

A high-speed analog optical phase modulator based on chiral smectic an d cholesteric liquid crystals is discussed. The chiral smectic liquid- crystal device functions as a variable-orientation half-wave retarder, whereas the polymer cholesteric liquid-crystal film acts as a polariz ation-preserving mirror. We use circular Jones calculus to describe op tical phase modulation, using a half-wave retarder of variable orienta tion acting on circularly polarized light. The phase induced by this m odulator is achromatic. Analog phase modulation of nearly 360 degrees is demonstrated with a device switching time of 200 mu s at 25 degrees C. (C) 1995 Optical Society of America