The Third Infrared Window

Long wave infrared (LWIR) and mid-wave infrared (MWIR) sensors and cameras have been used in military settings for detecting human activity through thermal emissions. Using the short wave infrared (SWIR) portion of the spectrum extends unique capabilities that often compliment LWIR and MWIR imaging. Until recently, the only way to see in this part of the spectrum was to use large, cryogenically cooled sensors. However, Sensors Unlimited of Princeton has produced small, uncooled cameras using the new indium gallium arsenide (InGaAs) semiconductor material. This application note discusses SWIR cameras and the benefits they offer in opening up the third and final window of the infrared spectrum.