Tempo-spatially modulated imaging spectropolarimetry based on polarization modulation array

Abstract

In this paper, we propose an instrument concept based on a polarization modulation array for the simultaneous measurement of the irradiance, spectrum, and polarization states of the target of interest. Using a group of retarders and polarizers oriented in specific directions, the full set of Stokes parameters can be determined directly without internal moving parts or extensive calculations. The polarization array consists of two retarders and four linear polarizers located at the incident aperture, so that the incident light is divided into four separate modulation channels. To measure the modulated spectra, we include an interference spectrometer based on the Savart polariscope principle in the system and retrieve the polarization spectra by Fourier transform. We apply a tempo-spatially modulation mode in the scheme to extract the multi-dimensional data of each point in the field of view. The system's performance, especially the capability for Stokes spectra measurement, is verified through both computer simulation and laboratory experiments. Possible sources of error are also analyzed.