Sur le phénomène d'absorption optique anormale des couches minces metalliques

Abstract

For some metals deposited in the form of thin films on a transparent support (glass or quartz) one has evidence of an absorption band which does not correspond to any transition likely to occur for an isolated atom, and which is not found in the bulk metal. The position of the maximum of this anomalous absorption band shifts toward longer wavelengths when the thickness of the layer is increased. The experimental study was carried out with gold, silver, copper, iron, cobalt, nickel, gallium, indium, and thallium. This phenomenon seems to be essentially due to the granular structure of the thin layers investigated.