Mueller-matrix measurement using the four-detector photopolarimeter

A scheme for complete, accurate, and fast determination of the Mueller matrix M of elastic light scattering by a given sample is presented. The Stokes vector of the scattered radiation is virtually instantaneously measured using the recently described four-detector polarimeter (FDP) [Opt. Lett. 10, 309 (1985)] for various input polarizations generated by a fixed polarizer followed by a quarter-wave retarder (QWR) of adjustable fast-axis azimuth C. The output signal vector I of the FDP is recorded at four or more settings of C. If the periodic function I(C) is Fourier analyzed, a series of four terms is obtained whose coefficients determine M column by column. The QWR azimuth C can be changed manually, by a stepping or synchronous motor, or by Faraday-cell magneto-optical rotation, leading to various semiautomatic and fully automatic modes of operation with a range of speed to suit various applications.