Two-dimensional plasmonic metamaterials

Abstract

Fabrication of three-dimensional negative refractive index materials in the visible range faces numerous technological challenges. On the other hand, many new concepts and device ideas in the optics of metamaterials may be demonstrated much easier in two spatial dimensions using surface plasmon polaritons. Here we demonstrate these concepts and devices using novel multilayer two-dimensional photonic materials consisting of alternating layers of positive and negative refractive index. By changing composition and geometry of the layers, the effective anisotropic refractive index of the material may be continuously varied locally from large negative to large positive values. This approach may find applications in many novel nanophotonic devices, which enable efficient control of light propagation on submicrometer scale. This becomes possible because of the considerably improved figure of merit of the plasmonic metamaterials compared to the typical figures of merit of their three-dimensional counterparts.