Oblique and normal incidence photometric return-path ellipsometers for isotropic and anisotropic surfaces

Photometric (autocollimation) return path ellipsometers (RPE) are described that operate at oblique and/or normal incidence for the examination of optically isotropic and anisotropic surfaces and thin films. Four automation schemes are proposed with polarizing/analyzing optics that consist of: 1) a rotating polarizer, 2) rotating polarizer and depolarizer, 3) rotating half-wave retarder and fixed polarizer, or 4) rotating polarizer and fixed polarizer. In all cases, it can be shown how the surface ellipsometric parameters ( psi and Delta ) can be retrieved from a photoelectric signal by simple Fourier analysis.