Lockheed Martin Corporation

Mark A Dodd

Bruno J Evans

Lewis Taylor Claiborne

Gary Kim Jenkins

An infrared detector array includes a plurality of detector pixel structures, each having a plurality of coplanar sections responsive to different bands of infrared radiations. Each section of a pixel structure comprises a plurality of elongate quantum well infrared radiation absorbing photoconductor (QWIP) elements. The group of QWIP elements are spaced such that they comprise a diffraction grating for the received infrared radiation. Top and bottom longitudinal contacts are provided on opposite surfaces of the QWIP elongate elements to provide current flow transverse to the axis of the element to provide the required bias voltage. An infrared radiation reflector is provided to form an optical cavity for receiving infrared radiation. A plurality of detector pixel structures are combined to form a focal plane array. Each pixel structure section produces a signal that is transmitted through a conductive bump to a terminal of a read out integrated circuit. The group of signals from the detector pixel structures produces a multi-band (color) image corresponding to the received infrared radiation.

Multi-band infrared photodetector

A sensor assembly for imaging passive infrared (IR) scenes and active laser radar (LADAR) scenes and for generating multi-dimension image data sets, and a method for same. A two-dimensional semiconductor imager sensitive to both passive IR radiation and active LADAR radiation when used in conjunction with subsequent signal processing creates a two-dimension passive image data set and a three-dimension active image data set with common x and y coordinates. The passive image data set is collected substantially proximate in time with the active image data set. The two image data sets are combined to form a multi-dimension image data set with the surface of three-dimensional objects indicating heat emission. The sensor assembly applies to burst illumination LADARs operating at a variety of wavelengths and passive IR detection in the middle wavelength IR (MWIR) or long wavelength IR (LWIR).

Sensor assembly for imaging passive infrared and active LADAR and method for same

An infrared detector array includes a plurality of detector pixel structures, each of which comprises a plurality of elongate quantum well infrared radiation absorbing photoconductor (QWIP) elements. The group of QWIP elements are spaced such that they comprise a diffraction grating for the received infrared radiation. Top and bottom longitudinal contacts are provided on opposite surfaces of the QWIP elongate elements to provide current flow transverse to the axis of the element to provide the required bias voltage. An optical cavity enhancement coating applied to the surface of the elements. The coating can be applied as to fill the space between the elements and extends above the top of the array if desired. The coating may be applied in multiple layers. An infrared radiation reflector is provided to form an optical cavity for receiving infrared radiation. A plurality of detector pixel structures are combined to form a focal plane array. Each detector pixel structure produces a signal that is transmitted through a conductive bump to a terminal of a read out integrated circuit. The group of the signals from the detector pixel structures produces an image corresponding to the received infrared radiation.

Optical cavity enhancement infrared photodetector

An electromagnetic sensor includes top and bottom longitudinal contacts on opposite surfaces of an electromagnetic absorbing structure. A grating is provided to diffract the electromagnetic radiation. A reflector operating in conjunction with the grating creates an electromagnetic cavity leading to the formation of a standing electromagnetic wave at a resonant frequency within the electromagnetic absorbing material. The addition of a highly electrically conductive layer to the perimeter of the electromagnetic absorbing material further defines the electromagnetic cavity. In particular, the conductive layer serves to create boundary conditions which enhance the absorption of electromagnetic radiation. Such a design applies to a class of electromagnetic sensors known as quantum well infrared photodetectors (QWIPs).

Resonant cavity field enhancing boundary

An infrared photocathode comprises an infrared radiation absorbing structure based on multiple quantum well (MQW) material on top of an electron conducting contact layer having a negative electron affinity back surface. In the first photocathode, a top contact layer is etched to form a transmissive diffraction grating to aid photon absorption in the MQW material. In the second photocathode, a plurality of spaced apart MQW structures form a diffraction grating which aids photon absorption in the MQW material.

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Arlington, TX, United States of America

Mark A Dodd