Optical Properties of Thin Metallic Films in Island Form

Abstract

The optical absorption of island films of gold was studied as a function of island density, as determined from electron micrographs and film thickness. The absorption band resulting from a bounded plasma resonance in the particles was shifted to longer wavelengths as the island density increased. The position of the band was that predicted by the Maxwell Garnett theory for island films with spherical particles. As the particles became smaller the absorption band was broadened because the mean free path of the electrons in them was reduced.