Solid memory medium and information reproduction system using the medium

Abstract

A memory medium for information storage and reproduction and an apparatus for reading information from the memory medium are set forth herein. The memory medium includes a solid storage layer formed of a pyroelectric and electro-optic material, and information is stored in the medium through local residual polarization of the layer owing to the pyroelectrical property of the material. The apparatus includes: (a) a light source for emitting a laser beam toward the medium; (b) a power source for applying electric power to the light source; (c) an optical system for converging the beam on the layer, so as to form a beam spot with a suitable size; (d) a sensing device for detecting an intensity of a laser beam reflected by, or a laser beam transmitted through, the layer, the intensity being changed owing to variation in refractive index of the layer due to the local residual polarization, the changes in the refractive index being based on the electro-optical property of the material, the sensing device generating a detection signal indicative of an intensity of the detected beam; and (e) a control device responsive to the sensing device, for generating a reproduction signal corresponding to the detection signal, the reproduction signal being used for the information reproduction.