High contrast polarization sensitive quantum well infrared photodetectors

The responsivity of polarization sensitive quantum well infrared photodetectors with small pixel size (down to 20 mu m) is investigated. It is shown that pixels suitable for integration into very large focal plane arrays (1000x1000) can discriminate the polarization of the incoming signal. A responsivity contrast higher than 60% is obtained although the grating size is reduced to only six periods. The quantum efficiency and polarimetric capabilities can be both optimized with the same grating parameters. (C) 2007 American Institute of Physics.