Simple near-monostatic Mueller polarimeter

Inferring material properties from active or passive polarimetric remote sensing requires knowledge of the polarized bidirectional reflectance distribution function (P-BRDF). To encourage and simplify the process of measuring the P-BRDF of materials in the monostatic or near-monostatic configurations seen in lidar and other active remote sensing systems, we describe the design, build, and operating procedure for a simple near-monostatic polarimeter. The described system operates at 1064 nm and with a transmitter-receiver separation of about 4°, but the design principles, alignment procedure, and measurement procedure can be directly applied to systems at other wavelengths or separation angles. Also included are the control and data analysis software for the instrument we deployed, and a small selection of retrievals from the instrument.