An optical memory system for storage and retrieval of digital data using a source of writing light in the visible light range and a separate source of near infrared, polarized reading light. The writing light is amplitude modulated by a signal containing the digital data to be stored. Horizontal and...http://www.google.de/patents/US4757472?utm_source=gb-gplus-sharePatent US4757472 - Electrophotographic optical memory system
