Patent ID: 6331904
Filing Date: 2001-12-18
Classification: G02B,G03H,G06K,H04N

Abstract:
A holographic data storage and retrieval system comprising:a) a holographic storage medium;b) an optical system comprising a concave mirror M.sub.1 and a convex mirror M.sub.2, having their reflective surfaces opposing each other;c) a reference beam R which propagates through said optical system and is incident on said storage medium, wherein said reference beam R comprises sequential portions:a portion R(1) which is incident on said concave mirror M.sub.1 ;a portion R(2) which is reflected by said concave mirror M.sub.1, and is incident on said convex mirror M.sub.2 ;a portion R(3) which is reflected by said convex mirror M.sub.2 and is incident on said concave mirror M.sub.1 ;a portion R(4) which is reflected by said concave mirror M.sub.1, and is incident on said storage medium; andd) a signal beam which bypasses said optical system, and is incident on said storage medium, said signal beam interfering with said reference beam R in said storage medium.