Interaction of Solid State Plasmon with Radiation II. Optical Absorption of Thin Metal Films

Abstract

Absorption cross section of p -polarized light in thin metal films is calculated microscopically as well as macroscopically. The absorption is of reasonance type at, the plasma frequency of the metal, if the imaginary part of the dielectric constant is sufficiently small. The absorption cross section per electron is inversely proportional to the film thickness. The elementary process of this resonance absorption is identified with the excitation of plasma oscillation in the film. The calculated cross section is of the order of 10 -17 cm 2 per electron for Al of 100 A thickness and may easily be detected experimentally.