Optical Constants of Silver, Gold, Copper, and Aluminum II The Index of Refraction n

Abstract

The reflectivities of Ag, Au, Cu, and Al were measured at an angle of incidence of 45°, in the wavelength range of 0.40μ to 0.95μ at glass-metal and air-metal interfaces. These reflectivities, together with previously determined values of the absorption coefficient k, were used to calculate the index of refraction n. Samples were prepared by evaporation and deposition from the vapor. The important experimental results are: (1) The ratios of the reflectivities in the s plane to those in the p plane agreed with the theoretical values. This result indicates that the boundary conditions required for the application of the equations of electromagnetic theory have been satisfied. (2) Ageing and annealing resulted in increased reflectivity at both air-metal and glass-metal interfaces. (3) The values of n obtained from aged or annealed samples were in many cases considerably lower than previously published values.