This letter reports preliminary results of experiments involving the storage of high-efficiency holograms in evaporated thin films of arsenic trisulfide (As2S3). Both simple gratings and holograms of complex data masks have been recorded in the films by direct exposure with no subsequent processing. Diffraction efficiencies of up to 80% have been measured for two-beam gratings. Several possible mechanisms are suggested to explain the observed results.

The optical-storage effect in evaporated films of arsenic trisulfide (As2S3) has been investigated. The physical and chemical aspects of the films were studied using a combination of etching, x-ray diffraction, ir spectroscopy, and annealing experiments. This study of the As2S3 optical-storage medium has culminated in the development of a physical model involving three well-defined states for the medium.

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A basic feasibility study has been made on a ferroelectric-photoconductor optical storage medium utilizing bismuth titanate and zinc selenide. Both the theory of device operation and experiment are described. Coincident light and electric field are used for WRITE and ERASE functions. The nondestructive READ operation is based on the birefringence properties of the bismuth titanate. Optical-electrical measurements, pattern storage and hologram storage are described. Holographic gratings as fine as 1.261 were stored. The WRITE energy was approximately lOpJ/(mm)'. Diffraction READ effciencies of approximately .01% were measured. The ferroelectric photoconductor optical storage medium compares favorably with other erasible media.