Snapshot imaging spectropolarimeter utilizing polarization gratings

Measurements of complete polarization and spectral content across a broad wavelength range of a scene are used in various fields including astronomy, remote sensing, and target detection. Most current methods to acquire spectral and polarimetric information need moving parts or modulation processes which lead to significant complexity or reduce sampling resolution. Here we present a novel snapshot imaging spectropolarimeter based on anisotropic diffraction gratings known as polarization gratings (PGs). Using multiple PGs and waveplates, we can acquire both spectrally dispersed and highly polarized diffractions of a scene on a single focal plane array, simultaneously. PGs uniquely produce only three diffracted orders (0 and ±1), polarization independent zerothorder, polarization sensitive first-orders that depend linearly with the Stokes parameters, and easily fabricated as polymer films suitable for visible to infrared wavelength operation. The most significant advantage of our spectropolarimeter over other snapshot imaging systems is its capability to provide simultaneous acquisition of both spectral and polarization information at a higher resolution and in a simpler and more compact way. Here we report our preliminary data and discuss the cogent design of our imaging spectropolarimeter.