Reflection of Light from Gold and Silver Plasmon Films: A Comparison of Experiment and Theory

The spectra of light reflection by plasmonic metal films deposited in vacuum on dielectric substrates and subsequently annealed at high temperatures are investigated. To explain the optical properties of plasmonic films, a theoretical model of a plane-layered metal-dielectric medium is used. One of the layers of such a structure has the dielectric constant of the metal under study, and the second layer has the dielectric constant calculated within the Maxwell-Garnett approximation for a heterogeneous medium consisting of a suspension of metallic nanoellipsoids in air. The introduction of this layer makes it possible to qualitatively take into account the inhomogeneities of the plasmon film surface. It is shown that the developed model allows a number of features in the experimental reflection spectra to be explained.