US 5,291,055 AGranted

Resonant infrared detector with substantially unit quantum efficiency

AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration

InventorsJam Farhoomand, Robert E. McMurray, Jr.

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Abstract

A resonant infrared detector includes an infrared-active layer which has first and second parallel faces and which absorbs radiation of a given wavelength. The detector also includes a first tuned reflective layer, disposed opposite the first face of the infrared-active layer, which layer reflects a specific portion of the radiation incident thereon and allows a specific portion of the incident radiation at the given wavelength to reach the infrared-active layer. A second reflective layer, disposed opposite the second face of the infrared-active layer, reflects back into the infrared-active layer substantially all of the radiation at the given wavelength which passes through the infrared-active layer. The reflective layers have the effect of increasing the quantum efficiency of the infrared detector relative to the quantum efficiency of the infrared-active layer alone.

Claims21

Dependent claims

A resonant infrared detector comprising:

an infrared-active layer for absorbing radiation of a given wavelength and including first and second parallel faces;
a first reflective layer, disposed opposite said first parallel face of said infrared-active layer and having a reflectivity tuned to the absorptivity of said infrared-active layer, for reflecting a specific portion of radiation incident on said first reflective layer during each pass of said radiation through said detector and for allowing a specific portion of said incident radiation at said given wavelength to reach said infrared-active layer;
and
a second reflective layer, disposed opposite said second parallel face of said infrared-active layer, for reflecting back into said infrared-active layer substantially all of the radiation at said given wavelength that passes through said infrared-active layer, whereby said first and second reflective layers increase the quantum, efficiency of said infrared detector relative to the quantum efficiency of said infrared-active layer alone,
wherein said first reflective layer has a reflectivity R and said infrared-active layer has an absorptivity (1-A) per single pass of radiation through said infrared-active layer, and R and A substantially satisfy the following equation:
R=A.sup.2.

3 more elements

Dependencies are inferred from the claim text.