Sub-second imaging speed Mueller matrix microscopy for observing dynamic growth of banded spherulites

Mueller matrix microscopy (MMM) is powerful for anisotropic material characterization through comprehensive polarization analysis. However, conventional MMM relying on controlled rotating retarders suffers from speed limitations, hindering its application in the structural analysis of many processes. Here, we constructed an optical rotary encoder based MMM (Fast-MMM) for precise analysis of complete Mueller matrix within 0.5 s. Through the precise angle tracking of dual continuously rotating retarders by optical rotary encoders and integral parameter method for dynamic imaging calibration, Fast-MMM was achieved without sacrificing accuracy and photon-throughput efficiency. The dynamic growth of banded spherulites was quantified by the designed Fast-MMM: the heterogenous growth rate of banded spherulites during cooling from the melt was vividly observed. Our system has offered a novel strategy for the sub-second analysis of dynamic materials through polarization optical properties with complete Mueller matrix imaging.