Optical Anisotropies in Thin Films of Silver and Gold

Thin films of silver and gold deposited at 45° exhibit anisotropies in normal incidence transmittance, reflectance and absorptance. The magnitudes of these anisotropies are typically about a few percent. An interesting characteristic feature, a double change in sign, is believed to be caused by the globular nature of these films during the early stages of growth. In thicker films, with a transmittance of a few percent, the magnitude of the anisotropy is essentially zero. When deposition is stopped for films in the globular state, the anisotropies change with time, more or less along a reverse deposition growth path which may include change of sign.