The design and fabrication of a micropolarizer array for imaging polarimetry is described for the 3-5-mwavelength region. Each micropolarizer consists of a 475-nm-period Mo wire grid in a 16 m ϫ 16 m aperture. Interference lithography is used to generate the small grating features through an etch mask layer. Arrays of 256 ϫ 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.

An attractive approach to realizing a real-time imaging polarimeter is to integrate an array of polarizationsensitive filters directly onto the focal plane array. This has the advantage of allowing all of the requisite polarization data to be acquired within each image frame. In this paper we discuss the design, fabrication, and performance of a diffractive optical element (DOE) that fulfills this requirement. The DOE consists of an array of broadband form birefringent quarter-wave plates and wire grid polarizers which are designed to allow the measurement of all four Stokes vector components for each image pixel.

High spatial frequency metal gratings have long been recognized as an effective polarizer option for the infrared portion of the spectrum.1 Numerous applications can benefit from the development of arrays of such wire-grid polarizers in which subsets of the polarizers have arbitrary angular orientations. In this paper we describe the design and fabrication of an array of small aperture polarizers (i.e., micropolarizers) for the 3-5 μm wavelength range.