White light Sagnac interferometer polarimeters

摘要

Snapshot imaging polarimeters comprise Sagnac interferometers that include diffraction gratings situated to produce shear between counter-propagating optical fluxes produced by a polarizing beam splitter. The counter-propagating, sheared optical fluxes are focused onto a focal plane array to produce fringe patterns. The fringe patterns correspond to a scene polarization distribution modulated onto a spatial carrier frequency associated with a diffraction order. Multi-blazed gratings can be used so that modulations at a plurality of spatial frequencies are produced, with each spatial frequency corresponding to a spectral component of an input optical flux. Modulated fringe patterns can be demodulated to obtain scene Stokes parameter distributions.

主权项

1. An apparatus, comprising:
a Sagnac interferometer that includes a pair of diffraction gratings so as to produce a dispersion compensated shear between first and second portions of an input light flux, the Sagnac interferometer comprising a polarizing beam splitter that directs the first and second portions of the input light flux along respective interferometer optical paths to the pair of diffraction gratings; a polarization analyzer situated to receive a combination of the sheared first and second portions of the input light flux and produce an associated output light flux; a detector situated to receive the output light flux and produce an image signal; and an image processor that produces a polarization image based on the image signal.