Micropolarizer array for infrared imaging polarimetry

The design and fabrication of a micropolarizer array for imaging polarimetry is described for the 3–5-µm-wavelength region. Each micropolarizer consists of a 475-nm-period Mo wire grid in a 16 µm×16 µm aperture. Interference lithography is used to generate the small grating features through an etch mask layer. Arrays of 256×256 micropolarizers at three distinct angular orientations have been fabricated that permit the measurement of the first three Stokes vector components in each pixel of an imaging polarimeter. An imaging system composed of a micropolarizer array integrated directly onto a focal plane array has been assembled, and initial testing has been performed.