Development of a dual-band LWIR/LWIR QWIP focal plane array for detection of buried land mines

We report on the development and testing of a new dual-band infrared (IR) focal plane array (FPA) specifically designed to detect buried land mines. The detector response spectra were tailored to take advantage of the sharp spectral features associated with disturbed soils. The goal was to have a "blue" channel with peak response near 9.2 mum and a "red" channel with maximum response at 10.5 mum. The quantum well infrared photodetector (QWIP) is particularly suited for this application because of the flexibility available in designing the peak wavelength of the detector and the relatively narrow width of the response spectrum. FPAs were produced and tested under the U. S. Army Research Laboratory's Advanced Sensors Collaborative Research Alliance in co-operation with the Night Vision and Electronic Sensors Directorate. We report on laboratory measurements of the response spectra, the dark current as a function of operating temperature, and the conversion efficiency in both the blue and red channels. Imagery was taken in the field of buried anti-tank mines. The images were analyzed by combining the data from the two channels into single fused images.