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:
Oct. 04, 1977
Filed:
Sep. 10, 1975
I-Cheng Chang, Sunnyvale, CA (US);
Itek Corporation, Lexington, MA (US);
Abstract
An electronically tunable optical filter is described wherein an optical beam is diffracted by an acoustic beam the group velocity of which is noncollinear with the optical beam transmitted through the birefringent crystal medium. The frequency and the direction of the phase velocity of the acoustic wave are chosen for a given incidence direction of the optical beam so that the diffraction occurs for a band of optical frequencies centered about a predetermined optical frequency and a relatively large angular distribution of incident optical beams. The noncollinear acousto-optic filter has the following advantages: (i) it allows very simple coupling of optical and acoustic beams into the interaction medium, (ii) it allows the use of multiple transducers for increasing tuning range or varying resolution, (iii) it allows a broad class of crystals to be used as filter material, (iv) it has a large degree of freedom in the filter design for optimizing efficiency or angular aperture and throughput, realizing narrow or broad optical passband and (v) it provides the spatial separation of incident and transmitted light through the filter and thus can be operated without the use of polarizers.