Verhagen, Ewoldde Waele, ReneKuipers, L.Polman, Albert2011-12-162011-12-162011-12-16201010.1103/PhysRevLett.105.223901https://infoscience.epfl.ch/handle/20.500.14299/74928WOS:000284532900010We identify a route towards achieving a negative index of refraction at optical frequencies based on coupling between plasmonic waveguides that support backwards waves. We show how modal symmetry can be exploited in metal-dielectric waveguide pairs to achieve negative refraction of both phase and energy. Control of waveguide coupling yields a metamaterial consisting of a one-dimensional multilayer stack that exhibits an isotropic index of -1 at a free-space wavelength of 400 nm. The concepts developed here may inspire new low-loss metamaterial designs operating close to the metal plasma frequency.Photonic Band-GapVisible FrequenciesMetamaterialstext::journal::journal article::research article