Optical Measurements on Liquid Metals Using a New Ellipsometer

Abstract

A new kind of ellipsometer which employs continuously rotating sheet polarizers is described. It enables the restored azimuth Ψ and the differential phase change Δ for light reflected from a metal surface to be obtained very directly from null settings of a polarizer or analyzer with a precision of 0.1°. The instrument has been used to study the optical constants of liquid metals, especially mercury, in the wavelength range 0.4–0.7 μ. Particular attention was paid to the problem of surface contamination, and evidence is presented that a glow discharge is particularly effective in removing this. Measurements have been carried out on surfaces in contact with glass and quartz as well as upon free surfaces. The results are internally consistent but differ significantly from the predictions of the Drude free-electron theory.