Highly Sensitive Room Temperature Middle Infrared Detector

Aspen Systems proposes a novel highly sensitive imaging and visualizing detector of eye-safe coherent Middle Infrared (MIR) Radiation (2 - 5 microns). The detector can operate at room temperature with noise-equivalent power NEP < 10 {super -12} WHz (super -1/2}, response time tau < 2.0X10 {super -7} s and an active aperture of few square centimeters. In the detector, the middle infrared images are transformed into a negative image in the visible range. The detector utilizes the demonstrated MIR quenching effect of the probe visible radiation in direct-gap crystals, e.g. CdS. The detection is based on a new physical principle of interation-indirect absorption of the probe visible radiation followed by the collisions between the virtual Wannier-Mott and spherical excitons localized on donor atoms in a direct-gap semiconductor.In Phase I, the principle of detection based on the MIR quenching phenomenon will be analytically and experimentally studied. To fabricate a prototype, the CdS crystal's required dimensions and orientation will be identified along with the most efficient method of excitation. The design of the detector and its components will be performed. In Phase II, coupling of the visible image from the detector to a CCD and a special circuitry developed by Wright Laboratory will be examined.