Ferroelectric, conductivity and secondary emission characteristics of a KD2PO4light valve

An on-line electrical to optical input transducer capable of spatially modulating a collimated laser beam is a major element in a real-time coherent optical processor. The electron-beam addressed light valve has received considerable attention as such an image transducer. Real time correlation, spatial filtering and spectrum analysis have been demonstrated using this device. This paper emphasizes ferroelectric and conductivity measurements obtained for an electron-beam addressed KD2PO4crystal over the operating range from room temperature through the transition temperature to the crystal's Curie point. Since the device stores information at its -52°C operating temperature, real-time operation necessitates charge removal by secondary emission using a flood gun. Experimental data on the crystal's secondary emission curve, crossover potentials, and sticking potential will also be presented, and the effects of these device parameters on system operation, design, performance and lifetime will be discussed.