A midwave infrared camera ͑ c = 4.2 m͒ with a 320ϫ 256 focal plane array ͑FPA͒ based on type-II InAs/ GaSb strain layer superlattice ͑SLs͒ has been demonstrated. The detectors consist of an nBn heterostructure, wherein the SL absorber and contact layers are separated by a Al 0.2 Ga 0.8 Sb barrier layer, which is designed to have a minimum valence band offset. Unlike a PN junction, the size of the device is not defined by a mesa etch but confined by the lateral diffusion length of minority carriers. At 77 K, the FPA demonstrates a temporal noise equivalent temperature difference ͑NETD͒ of 23.8 mK ͑T int = 16.3 ms and V b = 0.7 V͒ with a peak quantum efficiency and detectivity at 3.8 m equal to 52% and 6.7ϫ 10 11 Jones, respectively.
A voltage-tunable multispectral 320 × 256 infrared imaging focal plane array (FPA) is reported. It is based on InAs/GaAs quantum dots infrared phototdetctors (QDIP) with GaAs and In 0.20 Ga 0.80 As capping layers, corresponding to the extended middle-wave infrared (5-8 μm) and long-wave infrared (8-12 μm) detection bands, respectively. The FPA shows a noise-equivalent temperature difference of 172 mK at an operating temperature of 67 K. Voltage-tunable multispectral imaging was also achieved. Since each of the detection spectra of the QD FPA can be individually tuned by engineering its QD capping layer, this approach offers great flexibility in designing of a multispectral FPA.
QmagiQ LLC, has recently completed building and testing high operability two-color Quantum Well Infrared Photodetector (QWIP) focal plane arrays (FPAs). The 320 x 256 format dual-band FPAs feature 40-micron pixels of spatially registered QWIP detectors based on III-V materials. The vertically stacked detectors in this specific midwave/longwave (MW/LW) design are tuned to absorb in the respective 4-5 and 8-9 micron spectral ranges. The ISC0006 Readout Integrated Circuit (ROIC) developed by FLIR Systems Inc. and used in these FPAs features direct injection (DI) input circuitry for high charge storage with each unit cell containing dual integration capacitors, allowing simultaneous scene sampling and readout for the two distinct wavelength bands. Initial FPAs feature pixel operabilities better than 99%. Focal plane array test results and sample images will be presented.
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