Surface plasmon and autocorrelation function for rough surfaces of silver deposits

Abstract

Optical measurements of reflectance of opaque silver deposits prepared under static ultrahigh vacuum are presented. The structure of those deposits was determined in situ, using a replication technique. It is shown that reflectance measurements with photons incident through vacuum exhibit a significant decrease near the surface-plasmon energy. That decrease is interpreted as due to photon-surface-plasmon coupling at the rough surface. Autocorrelation functions for those rough surfaces of silver are determined from electron microphotographs of the shadowed surface carbon replicas. These microphotographs were analyzed using a processing-data-system microdensitometer. It is shown that autocorrelation functions have a Gaussian form. The rms roughness height $\delta$ and the autocorrelation length $\sigma$ are deduced.