Mueller matrix ellipsometry with imperfect compensators

We describe the use of an ellipsometer having the configuration PCSC’A to determine the Mueller matrix of a linear optical system S, using imperfect compensators C and C′ and linear polarizer P and analyzer A. Two manual (16 intensity), one semiautomatic (rotating-compensator) and one fully automatic (dual rotating-compensator) methods are described. Real-time Fourier analysis (of both raw and reduced data) is used in the automatic methods to reduce random and systematic measurement errors. Calibration procedures given for each method permit Mueller matrix spectroscopy using (quasi-) achromatic retarders whose principal axes, as well as retardation and transmission ratios change slightly with wavelength.