Surface plasmon driven scalable low-loss negative-index metamaterial in the visible spectrum

Abstract

We demonstrate that surface plasmons of a thin metal film interacting with a periodic array of nano-structures around it can be utilized to make bulk negative index metamaterials at visible spectrum with simultaneously negative permittivity and permeability. These surface plasmon driven metamaterials have high figure of merit and can be tuned arbitrarily to operate at any wavelength in the visible spectrum and possibly at ultraviolet spectrum. We numerically demonstrate the idea by a metamaterial structure which exhibits a strong magnetic response resulting in a negative index of refraction in the green region of the electromagnetic spectrum at 536nm with a figure of merit of 3.67. We also demonstrate by simply changing the constituent material only, hence by modifying the underlying surface plasmon dispersion, that the operating wavelength of the structure can be blue-shifted to the violet region at 406nm with a figure of merit of 2.27. In contrast to the fishnet-structure based approaches for visible metamaterials, our proposed approach offers a more frequency scalable way of achieving negative index of refraction in the visible and possibly at ultraviolet wavelengths with high figure of merit.