Azimuth alignment in photoelastic modulation ellipsometry at a fixed incident angle

Abstract

A high intensity ratio technique is proposed to align all the azimuthal angles of a photoelastic modulation ellipsometric system in a fixed incident angle. This technique is used to determine the azimuthal orientations of the polarizer, the photoelastic modulator and the analyzer to the incident plane, Two pre-designed testing samples and two probing wavelengths for a thin film are introduced to locate the incident plane by the intensity ratio technique in a polarizer-sample-analyzer ellipsometric setup. Then, the azimuth of the pholoelastic modulator is directly obtained from two DC radiances separated by 45degrees. In addition to azimuth deviation, the ellipsometric parameter psi can also be determined from the same measurement for determining the incident angle on-line.