Multi-Spectral QWIP-LED Devices: A Feasibility Study.

Abstract : The recent advances in infrared sensing technology has made it possible to use infrared sensors to support environmental observations, surveillance, threat detection, tracking, and target identification. For space-based ballistic missile defense (BMD) related applications, the most important detector requirements are: high sensitivity, high uniformity, large format, and multicolor capabilities. Quantum well infrared photodetectors (QWIPs) are a relatively new candidate technology for BMD applications. The current Canadian QWIP technology is based on integration of the QWIP with a light emitting diode (QWIP-LED). As the infrared technology continues to advance, there is a growing demand for multispectral (or multicolor) detectors with better target discrimination and identification. The objects of this study are first to identify the current QWIP multi-spectral implementation techniques and then to adapt them to the new QWIP-LED imaging scheme. The scheme has its unique design constraints associated with the QWIP-LED architecture. Some inherent limitations of the QWIP-LED scheme to achieving simultaneous multispectral registration are also discussed. Several multicolor QWIP-LED implementations are described, including two-leads pixelless QWIP-LED devices with sequential multicolor registration and multi-leads bicolor QWIP-LED focal plane array with near 100% fill factor.