Hemispherical Reflectance of Metal Surfaces as a Function of Wavelength and Surface Roughness

摘要

Measurements of the hemispherical reflectance of metallic surfaces with controlled surface roughness were made using a sulfur infrared integrating sphere and a beckman DC2A spectrometer. The surfaces studied were ground glass and nickel coated with films of aluminum, gold, platinum, and nickel. The data indicate that beyond a certain ratio of surface roughness to incident wavelength, the normalized data for aluminum, gold, and platinum may be represented by a single curve. This was true for the unidirectional as well as the isotropic roughnesses. Although the nickel data deviated from this curve, the causes for this deviation are believed to be associated with high surface stresses caused by changes in the crystalline structure and are discussed. (Author)