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:
Jan. 30, 1996
Filed:
Nov. 18, 1994
Gerald J Iafrate, Raleigh, NC (US);
Mitra Dutta, Tinton Falls, NJ (US);
Paul H Shen, Howell, NJ (US);
Michael A Stroscio, Durham, NC (US);
The United States of America as represented by the Secretary of the Army, Washington, DC (US);
Abstract
An thermal imaging device having a transparent substrate, an active multiple quantum well (MQW) epilayer with bottom electrical contacts bonded to the substrate, wherein the substrate is cut such that its thermal expansion coefficient is matched or roughly matched to that of the MQW epilayer in the direction parallel to the long axis of the bottom contacts and so that the thermal expansion coefficient of the substrate is mismatched in a direction normal to the long axis of the bottom contacts. Infrared radiation incident on each unit cell of the n.times.m array will produce a temperature change .DELTA.T in the MQW which will produce stress normal to the long axis of the bottom contacts. The uniaxial stress produced by the temperature changes .DELTA.T breaks the rotation symmetry in the plane of the MQW structure. This will result in anisotropic mixing of the heavy and light holes in the MQW epilayer and thus, will result in an anisotropic excitonic absorption of the MQW epilayer, which can be detected and analyzed either electrically or optically.