Target Accuracy with Enhanced Situational Awareness
For the last few decades, the military has used long wave infrared (LWIR) and mid-wave infrared (MWIR) sensors and cameras for detecting human activity by thermal emissions. Humans, vehicles and other equipment stand out strongly when the environment is at a different temperature.
The short wave infrared (SWIR) portion of the spectrum offers unique capabilities, often complementary to LWIR and MWIR imaging. Imaging in SWIR uses reflected light, much like the slightly shorter wavelengths of the visible spectrum. Until recently the only way to see in this part of the spectrum was to use large, cryogenically cooled sensors. But beginning in 2003, Sensors Unlimited of Princeton, New Jersey began to produce small, uncooled cameras using a new semiconductor material, indium gallium arsenide (InGaAs). This remarkable material has peak sensitivity in the SWIR band, from 900 to 1700 nm.
For military applications, SWIR cameras open the third and final window in the infrared spectrum. Long wave (LWIR) and MWIR sensors have long been a staple of military applications. Both are thermal sensors which do an excellent job of sensing human activity when that activity is warmer than its surroundings. Unlike LWIR and MWIR, SWIR sees in reflected light, so objects and persons look very similar to how they look in visible light, giving the military an all-new capability.