PLASMONIC Ag-Linbo3 metamaterial: a study of dielectric and optical properties

Abstract

We report the optical and dielectric properties of a multilayer system constituted by ITO, an squarearrangement of Ag nanoparticles (NPs) on the uniaxial LiNbO3, the polymer PMMA and the substrate SiO2. We investigate the compositional and geometrical parameters dependences on the optical absorption of the stacked layers. The effective dielectric function of the ensemble aggregates of Ag NPs and uniaxial LiNbO3 crystal is treated through the extended Maxwell-Garnett approximation. The multilayer absorbance is determined by means of the Transfer Matrix Method. We demonstrate that an adequate choice of structural parameters such as NPs sizes, interparticle distances and layers thicknesses can produce an enhancement of optical absorption in the multilayer. In addition, we evaluate the dielectric modulus parameter of the effective medium layer in the perpendicular and parallel directions of the Ag NPs plane. For both directions, when the filling factor is big enough, we find the negative epsilon (NE) condition, typical characteristic observed in metamaterials.