Measuring Stokes parameters by means of a polarization grating

TLDR

Polarization gratings modulate the state of polarization, unlike ordinary gratings that affect amplitude or phase, and a simple example is a linearly polarized grating with periodically varying orientation. The grating produces first‑order diffracted beams with counter‑rotating circular polarizations, enabling achromatic measurement of a light beam’s Stokes parameters, with additional extensions noted.

Abstract

Ordinary gratings act on the amplitude and (or) the phase of a wave front. Polarization gratings produce instead a periodic modulation of the state of polarization. A simple grating of the latter type is constituted by a linear polarizer whose orientation varies periodically along a line. It is shown that, for a generic polarization state of the incident field, such a grating gives rise to first-order diffracted beams with counterrotating circular polarizations. It is also shown that such a grating can be used for measuring the Stokes parameters of a light beam in an achromatic manner. Several extensions are briefly discussed.