A report presents additional information on the devices described in “Noise-Reducing Slots in Quantum-Well Infrared Photodetectors” (NPO-20518), NASA Tech Briefs, Vol. 25, No. 6 (June 2001), page 6a. To recapitulate: it was proposed that incorporation of suitably dimensioned crossed slots into quantum-well infrared photodetectors (QWIPs) equipped with two-dimensional surface grating light couplers would reduce dark currents and increase detectivities. Going slightly beyond that proposal, the report proposes optionally filling the slots with low-index-of-refraction dielectric material. Going beyond the previous discussion, the report notes that finite-difference solution of the Helmholtz equations for electromagnetic coupling into a slotted QWIP leads to the conclusions that (1) the slotted QWIP acts as an array of leaky waveguides or weakly coupled cavity resonators; (2) coupling can be maximized by choosing the width, spacing, and index of refraction of the slots to obtain resonance at the desired wavelength of operation; and (3) the coupling in such a case is stronger and more broad-band, relative to the coupling into a nonslotted surface-grating QWIP.

This work was done by Daniel Wilson, Sarath Gunapala, Sumith Bandara, and John K. Liu of Caltech for NASA’s Jet Propulsion Laboratory. To obtain a copy of the report, “Slotted Quantum Well Infrared Photodetector for Reduced Dark Current and Enhanced Optical Coupling,” access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Electronic Components and Systems category.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to Intellectual Property group

JPL Mail Stop 202-233 4800 Oak Grove Drive Pasadena, CA 91109 (818) 354-2240

Refer to NPO-20586, volume and number of this NASA Tech Briefs issue, and the page number.

NASA Tech Briefs Magazine

This article first appeared in the June, 2002 issue of NASA Tech Briefs Magazine.

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