Small pitch, large format long-wave infrared QWIP focal plane arrays for polarimetric imagery

摘要

We report on the first demonstration of a large format (640×512), small pitch (20μm), polarization sensitive long-wave infrared focal plane array. The choice of quantum well infrared photodetectors allows the monolithic integration of the polarizing element (1D gratings) into the focal plane array. The performance (response, NETD) under natural light is identical to that of polarization insensitive focal plane arrays, with the same pitch. Polarization contrast capabilities are investigated experimentally and are shown to be compatible with polarimetric imaging needs. Responsivity contrasts higher than 35% are obtained, on square 18.6μm pixels. Preliminary results on extremely compact arrays (15μm pitch) are presented.