Surface plasmons in granular Ag-SiO2films

Abstract
We report the first observation of surface plasmons in a granular metal. The plasma frequency ωp in the Ag-SiO2 system is determined from plasma resonance absorption measurements over the entire range of composition from the continuous-metal-film limit to the isolated-metal-particle limit. The observed decrease in ωp with increasing insulator concentration is understood within the framework of the phenomenological Maxwell-Garnett theory.