We propose simple and good approximate equations for the reflectance of the perpendicular and parallel polarizations of light upon an isotropic absorbing medium deduced from the Fresnel coefficients of reflection. We also calculate the principal incidence and the pseudo-Brewster angle by using approximate expressions. These formulas are valid when the optical constants n and k of the surface are such that n2 + k2 » 1 and are more accurate than those used so far in the literature. The excellent agreement between approximate and exact values verifies the high accuracy of the given equations.
© 1988 Optical Society of America
Jacques Mouchart, "Infrared reflectivity of metallic surfaces," J. Opt. Soc. Am. A 5, 674-680 (1988)