Information storage in holograms.

摘要

A holographic storage system receives light having its linear polarisation rotated from a reference linear polarisation for carrying given information. The modulated light is stored as two distinct images in a photorefractive medium (10), the images carrying the same information but being complementary projections of linear polarisation rotations from the reference linear polarisation in a given rotational sense. The images are stored in the same volume portion of the medium. Upon readout, the two images arte converted into modulated electrical signals (Px, Py). To reproduce the information, one of the modulated electrical signals is divided into the other modulated electrical signal. A function of arc tangent of square root is introduced into the signal processing at the output portion of the system.