Negative refractive index in the near-UV from Au-coated CuO nanoparticle superlattices

Nanoparticle superlattices consisting of CuCl spheres coated with a gold (Au) nanoshell are shown to exhibit negative index of refraction in the near-UV regime. These predictions are based on calculations of the effective refractive index by use of the extended Maxwell-Garnett theory. The results for the refractive index are supplemented by multiple-scattering calculations of light-transmittance curves from finite slabs of naroparticle superlattices. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.