Anti-phase snapshot imaging polarimeter with high throughput based on polarization gratings

In this paper, a high-throughput anti-phase snapshot imaging polarimeter (ASIP) based on polarization gratings is proposed, which can be classified into a linear polarimeter and a full-Stokes polarimeter according to the number of detectable polarization parameters. The two configurations differ only in the addition of an extra polarization grating pair and a quarter-wave plate. The ASIP utilizes polarization grating pairs to perform light beam shearing and polarization state modulation. Subsequently, a polarizing beam splitter splits the modulated beams into s-polarized and p-polarized light, and the two polarized light components are then detected separately by two detectors to acquire anti-phase interference images. Simple addition and subtraction operations on the data received by the two detectors enable the acquisition of full-resolution S₀ and interference images of the remaining Stokes parameters, which are free from DC component interference. Meanwhile, the proposed ASIP eliminates the use of linear polarizers, which effectively improves the system throughput and the signal-to-noise ratio of frequency-domain channels, thereby significantly enhancing the demodulation accuracy of the measured Stokes parameters. In this paper, the theoretical models of the two ASIP configurations are derived in detail, simulation analyses are performed, and specific parameter designs are provided.