ELECTRO-OPTICAL MEMORY EMPLOYING FERROELECTRIC ELEMENT

摘要

A photoconductive-ferroelectric device is employed as an erasable storage medium for recording and reading light patterns. The ferroelectric material may be a bismuth titanate crystal and its polarization pattern (corresponding to the recorded light pattern) is read out by directing linearly polarized light at the ab-face of the crystal, at an angle to the c-axis of the crystal and preferably perpendicular to the b-axis of the crystal. With proper choice of the direction of linear polarization, the incident light is phase delayed different amounts in the differently polarized regions of the crystal and this difference in phase may be detected and employed as the basis for reconstructing the light pattern. Operation in this way is found to provide substantially greater readout efficiency than has been available heretofore.