Novel design and alignment of wire-grid diffraction gratings on a visible focal plane array

Abstract

A pixelated, wire-grid diffraction grating is designed, fabricated, aligned, and mounted on an active focal plane array of a camera operating in the visible. The resulting design of the pixelated wire-grid polarizer array eschewed the need for fine translational alignments and drastically reduced cross-talk between pixels detecting differing polarization states. Using common optomechanical elements in conjunction with a novel correlation-based alignment metric, we are able to achieve repeatable angular alignments to better than 0.004 deg between the focal plane array and the pixelated wire-grid polarizer array, both featuring 6.45 μm pixels. An on-chip, four-state, linear snapshot polarimeter is yielded in the detailed processes and raw image data from the instrument are presented.