Ellipsometry of anisotropic media

We examine various reflection ellipsometry arrangements to see what they measure when the reflecting stratification is anisotropic. We find that the simplest polarizer–sample–analyzer ellipsometer can determine the absolute squares and the real parts of ρp = (rpp + rsptan p)/(rps + rss tan P) or ρA = (rpp + rps tan A)/(rsp + rss tan A), depending on whether the polarizer angle P or the analyzer angle A is varied, the other being held constant. For ellipsometer arrangements that use a compensator or a polarization modulator, the real and the imaginary parts of ρA are measured when the compensator or the modulator is placed between the polarizer and the reflecting specimen, while the real and the imaginary parts of ρp are determined when the compensator or the modulator is placed between the sample and the analyzer.