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:
Sep. 27, 1988
Filed:
Jul. 30, 1987
Dana Z Anderson, Boulder, CO (US);
Jack L Feinberg, Manhattan Beach, CA (US);
Other;
Abstract
Changes in an image are detectable by a tracking novelty filter while an incorporated holographic medium is in disequilibrium. A suitably doped single-domain barium titanate crystal can serve as the holographic medium. Image information is imposed on a laser beam in the form of a spatially varying polarization across the beam cross section spatial position. The modulated beam is directed to the crystal, which cooperates with a polarizing beam splitter and a half wave plate to define a polarization conjugator. The conjugated beam is passed through the modulator a second time and then operated on by a beam splitter. When the crystal is in equilibrium with the incident laser light, the beam splitter directs minimal light to a detector. However, when an image change causes a change in the applied modulation, the changed image elements are intensified at the detector while the holographic medium is in disequilibrium. In alternative embodiments, phase is the variable modulated. The holographic medium can be arranged as a conjugator or a two-wave or four-wave mixer.