Lockheed Martin Corporation

Drs Network & Imaging Systems, LLC

Drs Rsta, Inc.

Lockhead Martin Corp.

Loral Vought Systems Corporation

Xylon LLC

Drs Sensors & Targeting Systems, Inc.

Pradip Mitra

Jeffrey Don Beck

Mark R Skokan

James Richard Wood

Lewis Taylor Claiborne

Chang-Feng Wan

Michael A Kinch

Bruno J Evans

John Marcel Dell

James E Robinson

Laurie Faraone

Lewis T Claiborne

Charlie A Musca

A radiation detector is provided that includes a photodiode having a radiation absorber with a graded multilayer structure. Each layer of the absorber is formed from a semiconductor material, such as HgCdTe. A first of the layers is formed to have a first predetermined wavelength cutoff. A second of the layers is disposed over the first layer and beneath the first surface of the absorber through which radiation is received. The second layer has a graded composition structure of the semiconductor material such that the wavelength cutoff of the second layer varies from a second predetermined wavelength cutoff to the first predetermined wavelength cutoff such that the second layer has a progressively smaller bandgap than the first bandgap of the first layer. The graded multilayer radiation absorber structure enables carriers to flow toward a conductor that is used for measuring the radiation being sensed by the radiation absorber.

Radiation detector having a bandgap engineered absorber

An imaging device includes a first semiconductor layer having a first surface and a second surface and a first photodetector having a first implanted region formed in the first semiconductor layer and a pad formed over the first implanted region. The imaging device also includes a readout circuit disposed over the first surface of the first semiconductor layer. The readout circuit has a plurality of contact plugs facing the first surface of the first semiconductor layer. The imaging device further includes a second semiconductor layer disposed below the second surface of the first semiconductor, a second photodetector having a second implanted region formed in the second semiconductor layer, and a metalized via extending through the first semiconductor layer and the second semiconductor layer and electrically connecting the second implanted region to a second of the contact plugs of the readout circuit.

Very small pixel pitch focal plane array and method for manufacturing thereof

A method for manufacturing an imaging device is provided. The method comprises forming a contact pad over a semiconductor substrate. The contact pad has a malleable metal. The method further comprises providing a readout circuit having a first side and a contact plug. The contact plug has a base affixed to the first side of the readout circuit and a plurality of prongs extending from the base away from the first side. The first side of the readout circuit is moved towards the substrate so that the prongs of the contact plug are pressed into the pad and displace a portion of the pad into a space defined by and between a first and a second of the prongs. Stop elements formed over the substrate are aligned with and contact stop elements provided on the readout circuit so that the prongs are inhibited from passing completely through the contact pad.

A diffraction grating coupled infrared photodetector for providing high performance detection of infrared radiation is described. The photodetector includes a three-dimensional diffractive resonant optical cavity formed by a diffraction grating that resonates over a range of infrared radiation wavelengths. By placing a limited number of p/n junctions throughout the photodetector, the photodetector thermal noise is reduced due to the reduction in junction area. By retaining signal response and reducing the noise, the sensitivity increases at a given operating temperature when compared to traditional photovoltaic and photoconductive infrared photodetectors up to the background limit. The photodetector device design can be used with a number of semiconductor material systems, can form one- and two-dimensional focal plane arrays, and can readily be tuned for operation in the long wavelength infrared and the very long wavelength infrared where sensitivity and noise improvements are most significant.

Diffraction grating coupled infrared photodetector

A tunable infrared detector is provided that includes a substrate, a bottom wavelength detector formed over the substrate, a top wavelength detector formed over the first wavelength detector layer, and an interferometer filter formed over the top wavelength detector layer and the bottom wavelength detector layer. The interferometer filter is operatively configured to pass a first wavelength associated with a first portion of a predetermined band and a second wavelength associated with a second portion of the predetermined band to the top wavelength detector. The top wavelength detector is operatively configured to detect each wavelength associated with the first portion of the predetermined band and to transmit each wavelength associated with the second portion of the predetermined band to the bottom wavelength detector. The bottom wavelength detector is operatively configured to detect each wavelength associated with the second portion of the predetermined band.

Spectrally tunable infrared image sensor having multi-band stacked detectors

A method and apparatus for stretching a pulse, shaping a stretched pulse, and modeling a stretched and/or shaped pulse are disclosed. An etalon has a port, a partially reflective surface, and a fully reflective surface. A base pulse is introduced into the etalon, and a plurality of portions of the base pulse propagating from the etalon are collected. The collected portions are then combined to generate a stretched pulse whose width is proportional to the width of the base pulse. This can be modeled by assigning a transmission factor value to each one of a plurality of tags and a reflection factor value to each one of the taps, excepting only one tap. A transport delay for is assigned to each tap to which a reflection factor value was assigned, wherein the transport delay is proportional to the width of a base pulse.

Method and apparatus for stretching an optical pulse

An avalanche photodiode is operated in avalanche mode at a selected reverse bias that achieves high gain and a reduced gain normalized dark current.

Method of operating an avalanche photodiode for reducing gain normalized dark current

A method of and apparatus for detecting diseased tissue based upon infrared imaging in two different bands of infrared wavelengths is described. The use of two series of infrared images taken in two different bands of infrared wavelengths increases sensitivity to the subtle temperature changes caused by diseased skin and tissue, especially in the case of cancerous tissue. By sensing skin temperature, the homogeneity thereof, the time variations thereof and the correlation between the two series of infrared images, the present invention decreases the rate of false positives and false negatives. The increased discrimination due to two series of infrared images allows for reliable detection of diseased or cancerous tissue even in the presence of skin tone variations such as birthmarks, tattoos and freckles. The present invention finds special application in the field of breast cancer detection where subtle skin temperature variations may readily be sensed using two series of infrared images.

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Colleyville, TX, United States of America

Pradip Mitra