A Fourier Ellipsometer Using Rotating Polarizer and Analyzer at a Speed Ratio 1:1

摘要

We propose theoretically a spectroscopic ellipsometer in which the polarizer and the analyzer are rotating synchronously in the same direction with the same angular speed. The light intensity received by the detector contains four components, one dc and three AC terms, with frequencies of 2ω, 4ω, and 6ω. The main advantage of the proposed ellipsometer is that one can extract the ellipsometric parameters Ψ and Δ from the AC Fourier coefficients without relying on the dc component which is considered to be a serious problem in rotating-analyzer or polarizer ellipsometers. This allows measurements in a semidark room without worrying about stray light problems, dark currents in detectors, and long-term fluctuations in light sources. The results from the simulated spectra of the complex refractive index of c-Si and Au are presented. The noise effect on the proposed ellipsometer was simulated and plotted for the two samples.