A High Capacity Holographic Storage System

Abstract

This paper describes a potential storage system that would provide 2²⁴ bytes of data with a random access of 2μsec, and a data rate of 50 megabytes/sec. The system discussed is organized as a block oriented optically accessed memory and utilizes holography as the storage mechanism. The information is stored holographically.

The holograms are recorded in a silver halide emulsion on a glass substrate providing a nonvolatile storage medium. This technology combines high bit densities with large positional tolerances. Each holographic block consists of 512 bytes of data which have been word organized. The plate is accessed by means of a laser beam which transfers, in parallel, an entire data block to a detector array.

The system consists of the following elements: a frequency doubled Nd:YAG laser operating at 5300A; a 15-stage digital light deflector subsystem which provides 32,768 randomly accessed positions, an information storage plate, means for changing plates, a silicon integrated photodetector array that converts the 512 bytes (64 x 72 bits) of optical data into electrical signals at a nominal 1