Study of the surface and bulk polaritons with a negative index metamaterial

Abstract

This work investigates the impact of surface and bulk polaritons on the optical properties, especially the reflectance, of a negative index metamaterial (NIM) sandwiched between different dielectric layers. Regime maps are developed to describe the polariton dispersion relations and to help understand the effect of the NIM layer thickness on the polariton resonance frequencies. It is shown that polaritons exist for both p and s polarizations in the same frequency region where the refractive index is negative; beyond this region, surface polaritons exist for p polarization only. For an NIM layer, the dispersion curves of a surface polariton and a bulk polariton are smoothly connected, suggesting that a surface mode can be converted into a bulk mode, and vice versa. In an attenuated total reflection configuration, the width of the gap between the prism and the NIM layer has a strong influence on the location and the magnitude of the reflectance minimum. Furthermore, surface polaritons may exist at a single boundary and enhance the energy transmission via photon tunneling. The results demonstrate that NIMs may be used to effectively "tune" the optical properties of a layered structure in connection with surface and bulk polaritons.