Abstract: 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.

Abstract: 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.

Abstract: 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).

Abstract: 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.

Abstract: A semiconductor based radiation detector utilizing a dual absorption layer system design to selectively respond to particular bands of incident radiation while rejecting others. Generally, a top absorption layer initially absorbs all radiation less than a cutoff wavelength. Radiation longer than the cutoff pass to a buried or second absorption layer. This second absorption layer has a smaller band gap energy corresponding with a larger cutoff wavelength than the top layer and is therefore responsive to longer wavelengths or radiation with lower energies. As such, preselected wavelengths or energy bands are detectable by the second layer while all other wavelengths or energy bands are either absorbed by the top layer or passed through both layers. The resultant absorption in the second layer is thereafter detectable to indicate the presence of the desired wavelength.