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:
Aug. 06, 1996
Filed:
Aug. 12, 1994
David H Chow, Newberry Park, CA (US);
Colin G Whitney, Tucson, AZ (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
A controllable infrared filter (22) includes a quantum well filter unit (24) operable to absorb infrared energy at a selected wavelength. The quantum well filter unit (24) has a quantum well layer (26) made of an infrared transparent semiconductor mate rial and a barrier layer (28, 32) of another infrared transparent semiconductor material epitaxially deposited on each side of the quantum well layer (26). There is structure for controllably introducing charge carriers into the quantum well layer (26), which may utilize a source of electrons from other semi conductor layers (36, 38) and an applied voltage, or may utilize a laser (76) that generates charge carriers in the quantum well layer (26). The filter (22) further includes a lens (44, 46) or other optical system for directing infrared radiation through the first barrier layer (28), the quantum well layer (24), and the second barrier layer (32). Fixed band pass optical filters may be used in conjunction with the controllable quantum well filters.