Recording of nonstationary images by MDSDM photosensitive structures containing a liquid crystal

The design and testing of an MDSDM spatial light modulator using 200-micron-thick 10-Mohm cm monocrystalline GaAs as semiconductor and a 5-10-micron-thick planar-orientation positive-dielectric-anisotropy liquid crystal (LC) as one dielectric are reported. When one face is illuminated with 633-nm light, the structure acts as a photovaractor, a photovaractor/rectifier, or a rectifier, depending on the supply voltage frequency (less than 1 kHz, 1-10 kHz, or more than 10 kHz, respectively). The responses to 250-msec light pulses are shown for different supply frequencies: optional indication of pulse start and end is achieved at 200-250 kHz, where photovaractor-mode response is suppressed by a factor of 100-1000. This implies that only nonstationary image components are recorded.