Resonant light interaction with plasmonic nanowire systems
  We compare the optical response of isolated nanowires, double-wire systems, and Pi-structures, and show that their radiation is well described in terms of their electric and magnetic dipole moments. We also show that both dielectric permittivity and magnetic permeability can be negative at optical and near infrared frequencies, and demonstrate the connection between the geometry of the system and its resonance characteristics. We conclude that plasmonic nanowires can be employed for developing novel negative-index materials. Finally, we demonstrate that it is possible to construct a nanowire-based "transparent nanoresonator" with dramatically enhanced intensity and metal concentration below 5 %. 
Viktor A. Podolskiy, Andrey K. Sarychev, Evgenii E. Narimanov,   Vladimir M. Shalaev