Abstract. A new high operating temperature (HOT) midwave infrared (MWIR) imaging core is experimentally evaluated for use in automated inspection of composite impact damage by line scan thermography (LST). This evaluation is undertaken as part of a broader effort to develop an autonomous inspection capability for aerospace composite structures, deployable by ground and aerial robotic systems. The performance of the HOT MWIR core is assessed against a high-performance cooled photon-detector camera, an uncooled microbolometer core and an uncooled microbolometer camera, on two carbon epoxy laminate test specimens: one containing flat-bottom-hole synthetic defects and the other barely visible impact damage (BVID) introduced by controlled low-velocity impact. These test panels are scanned using a 3-axis robotic LST apparatus, at speeds of 25 and 100 mm/s. The HOT MWIR core is shown to match the detection performance of the cooled camera, and to significantly outperform both microbolometers. The high performance of this core combined with its relatively low mass, size and power consumption offers an encouraging basis for the development of a drone-deployable LST inspection capability.
Ga-free InAs/InAsSb type-II superlattice (T2SL) photodetector for high operating temperature in the midwave infrared spectral domain