Tempo-spatially modulated Mueller matrix imaging polarimeter based on modified Savart polariscopes.

Mueller matrix polarization measurement technique, as a non-invasive and label-free, provides comprehensive optical information on polarization-related and structural characteristics of the measured target. It has been widely applied in biomedical, agricultural, and industrial fields. However, the traditional time-division modulation Mueller matrix measurement method requires multiple measurements, which suffers from long measurement time and susceptibility to cumulative errors from moving parts. The snapshot spatial modulation method can capture the target's interferograms and the full Mueller matrix element images in a single exposure, but it suffers from lower spatial resolution. To address the strengths and limitations of both temporal and spatial modulation, this paper proposes a tempo-spatially modulated Mueller matrix imaging polarimeter (TSM-MMIP). This approach is based on the Stokes imaging polarimeter with the modified Savart plates as the core device, allowing the acquisition of the 16 Mueller matrix elements of the target with only four measurements. Through computer simulation and experimental platforms, we validate that the structural similarity of Mueller matrix elements between input and output exceeds 0.85, which demonstrates the reliability and feasibility of the proposed method. In addition, we use a bee wing as a target to reveal the potential of this technique to analyze the polarization characteristics of targets by extracting and analyzing key parameters of the Mueller matrix.