Plasmon guided modes in nanoparticle metamaterials

Surface modes in nanostructured metallic metamaterial films are reported showing larger confinement than plasmons in metallic waveguides of similar dimensions, but in contrast to plasmons, the new modes have TE polarization. The metamaterial, formed by planar arrays of nearly-touching metallic nanoparticles, behaves as a high-index dielectric for the noted polarization, thus yielding well confined guided modes. Our results for silver particles in silica support a new paradigm for TE surface-wave guiding in unconnected nanostructured metallic systems complementary to TM plasmon waves in continuous metal surfaces. (C) 2008 Optical Society of America.