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A random access optical memory for write-read-write operation is proposed. The memory is designed on the basis of a nonvolatile magnetooptic photoconductor sandwich storage material (MOPS) that offers high optical sensitivity. The optical addressing part of the memory consists of an He-Ne laser, digital light deflection combined with passive beam splitting and simple optics. The addressing is organized in blocks of about 10(3) bits. First experimental results measured at a system model being developed in our laboratory are presented, as well as results of storage experiments at a magnetooptic photoconductor sandwich.

CdS in the form of a single crystal is a material exhibiting a steep band edge at the green argon wavelength of 0.515 microm. The thermal shift of this band edge is used to modulate the transmittance of a matrix addressed page-composer for binary data presentation. Short switching pulses in the range of 20 / 50 V applied to evaporated transparent heating elements produce within 100 microsec a 70 degrees C temperature shift in a thin CdS-crystal, being the key element of the page-composer. Contrast ratios of the transmittance of better than 800 and optical efficiencies of 50% are easily obtained in 10 / 20-microm thick samples. Fast parallel switching of twenty-five elements using time multiplex heating has been demonstrated with a 5x5 CdS-page-composer. A 16x18 matrix is being fabricated, and the implementation of larger arrays accessible in 1 msec appears feasible.

This paper gives optical design considerations and experimental results of a 20-stage digital light beam deflector consisting of a series of nitrobenzene Kerr cells and birefringent calcite prisms. The laser beam is deflected into a two-dimensional raster of 1024 by 1024 positions with a deflection rate of 500 kHz. The optical transmission of the deflector itself is 79% for green laser light. Data about background light and resolution as well as display examples showing alphanumerics and graphics are given.