Effect of surrounding medium on the optical properties of a two layersilver film

摘要

The effect of surrounding medium on the optical properties of a two layer silver film are investigated using an analytical model. We varied the media before the first layer, between the two layers, and after the second layer. We find that the optical properties of the film is dominantly determined by the medium between the two layers. The resonance wavelength red shifts when the medium between the two layers is changed from vacuum to water and then glass. The media before the first layer and after the second layer have little effect on the spectra of the film when the thicknesses of the layers are larger than 40 nm.