The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 20, 1999
Filed:
Mar. 18, 1997
Harold M Stoll, Rancho Palos Verdes, CA (US);
Northrop Grumman Corporation, Los Angeles, CA (US);
Abstract
A volume holographic memory has a spinning disk comprised of photorefractive medium, object beam optics configured to direct an object beam through the outer edge of the disk, and reference beam optics configured to simultaneously direct a reference beam through the outer edge of the disk. An angle multiplexer manipulates the reference beam to facilitate the formation of angle multiplexed volume holograms. The object beam and the reference beam cooperate within the photorefractive medium to sequentially form a plurality of sets of angle multiplexed volume holograms therein while the disk is spinning. A phase conjugator directs a conjugate reference beam back through the disk after the reference beam has previously passed therethrough, so as to form a conjugate object beam to facilitate read-out. Amplitude monitoring is provided to facilitate use of an exposure schedule. Path length monitoring assures consistent phase relationship between the object and reference beams for write and erase operations. Calibration of the angle multiplexer is provided.