Strain-Biased PLZT Input Devices (Page Composers) for Holographic Memories and Optical Data Processing

Abstract

PLZT-7/65/35 is a ferroelectric ceramic with strong electrooptic properties and memory; it is switched through transparent electrodes when mechanically strained. Matrix addressed x-y page composers for interfacing electrical and coherent optical systems are being fabricated with PLZT. Switching voltages are 50-300 V. Optical efficiencies greater than 40% have been achieved. Strains near 2.4 x 10(-3) mm/mm permit half-wave retardation switching in 100-micro-thick plates with 80-V read-in and 190-V erase levels (60 Hz hysteresis data). A 128 x 128 element array can operate at 10(7) bits/sec with 10-microsec switching in a row at a time mode. Half-select disturbances affect contrasts. Applications in displays are also feasible.

Controlled transparencies based on magnetic crystals

“…The optical contrast and response time of orthoferrite and garnet controlled transparencies are several times better than those of nonmagnetic transparencies. 20 Moreover, magnetic controlled transparencies do not exhibit ageing and are ideally suitable for storing the recorded information. A shortcoming of magnetic transparencies is the relatively low optical efficiency which has a theoretical limit of ~ 30% for the best of the known material in visible light.…”