Tunable plasmon polaritons in arrays of interacting metallic nanoparticles

Abstract

We consider a simple cubic array of metallic nanoparticles, each supporting a localized surface plasmon, and study theoretically the properties of the propagating plasmon polaritons resulting from the near-field dipolar interaction between the nanoparticles and the coupling to light. Remarkably, we show that the polaritonic band gap, the dielectric function and the reflection coefficient of the metamaterial can be significantly modulated by the polarization of light. We unveil how such an anisotropic behavior in a plasmonic metamaterial is crucially mediated by the dipolar interactions between the nanoparticles despite the symmetry of the underlying lattice. Our results thus pave the way towards the realization of tunable quantum plasmonic metamaterials presenting interaction-driven birefringence.