Single-Pulse Mueller Matrix LiDAR Polarimeter: Modeling and Demonstration

We introduce a new LiDAR polarimeter architecture enabling measurement of a large subset of a target Mueller matrix in a single ~10-ns laser pulse; this may be beneficial for remote sensing from moving platforms in terrestrial and defense applications. We will numerically explore the measurement accuracy dependence on various hardware parameters and signal-to-noise ratio and provide an experimental demonstration. For the transmitter, we direct the laser pulse through an electrooptic (EO) phase modulator wherein a high-voltage ramp is synchronously applied. As the laser pulse propagates through the crystal, the voltage ramp induces a time-varying birefringence which results in a well-defined time-varying polarization across the laser pulse temporal envelope used to illuminate the target. The architecture can measure as many as 12 elements of target Mueller matrix by employing three polarization state analyzers. Knowing the temporal distribution of the transmitted polarization signal and employing fast detectors in the polarization analyzers, the Mueller matrix elements are estimated. We will introduce a model describing the transmitted and received signal polarization temporal distribution and show how Mueller matrix elements can be obtained. We will demonstrate the concept using a 10-ns laser pulse, an EO phase retarder in the transmitter and using two polarization analyzers in the receiver to measure nine elements of the Mueller matrix in a point and shoot configuration. Measurements will be compared to a theoretical reference to assess accuracy.