A discussion is presented of the practical considerations involved in wavelength-scanning polarization-modulation ellipsometry. Emphasis is placed on factors affecting accuracy and precision and on the alignment of the optical elements. The system described is used to measure the optical properties of air-cleaved KCI and of clean and tarnished Ag surfaces in ultrahigh vacuum in the 250–650-nm range.
Victor M. Bermudez and Victor H. Ritz, "Wavelength-scanning polarization-modulation ellipsometry: some practical considerations," Appl. Opt. 17, 542-552 (1978)