Error analysis of a simple and accurate optical coherent ellipsometer



The polarization modulation of optical coherent ellipsometry (OCE) is provided by the coupling between two highly correlated orthogonal polarizations with slightly different frequencies. Error of the sample-analyzer (SA) OCE is analyzed using the Stokes–Mueller formalism to include samples with roughness. Sample's depolarization will degrade the coherency of the incident two-frequency laser beam, and the degradation is more serious for smaller sin 2ψ. For the simplest SA OCE with the analyzer angle at 45° from both polarizations, the misalignment of the analyzer affects only the measured dc signal but not the beat signal; and the extinction of the analyzer affects only the beat signal but not the dc signal. This SA OCE is used to measure the polarization properties for a few samples to demonstrate its applicability. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)