Polarization sensitive QWIP thermal imager

A polarization-sensitive thermal imager has been assembled using a quantum well infrared photodetector (QWIP) focal plane array (FPA) with peak responsivity in the long-wave infrared spectral band near 9 mum. Polarization-dependent responsivity is achieved by etching linear gratings onto each pixel during QWIP FPA fabrication, with adjacent pixels having orthogonal grating orientation. The direct integration of the gratings with the pixels eliminates all pixel registration errors encountered with previous infrared polarimetry instruments. We present here details of the FPA and thermal imaging system design and performance and show examples of polarization-enhanced imagery. (C) 2001 Elsevier Science B.V. All rights reserved.