Backscattering Mueller-matrix photopolarimeter with nonreciprocal polarizing-analyzing optics.
To measure all 16 elements of a backscattering Mueller matrix, a polarimeter of the return-path configuration must be used with nonreciprocal polarizing-analyzing optics. Nonreciprocity is essential to make the same optics behave differently for the forward and backward waves. A design of this type is described in which the speed of rotation of a quarter-wave retarder is made to appear different for the incident and backscattered beams by use of Faraday cells with appropriate excitations. The same performance as of a previously described single-path polarimeter [Opt. Lett. 2, 148 (1978)] is realized. Applications are anticipated in polarization lidar studies and also to extend perpendicular-incidence ellipsometry to the characterization of depolarizing (e.g., rough) anisotropic surfaces.
Azzam
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RM