Plasmonic nanoparticle doped medium for frequency selective waveguide coupling

Abstract

We present a powerful technique for frequency selective coupling of dielectric waveguides by incorporating plasmonic nanoparticles within the structure. This is achieved by the inclusion of an optimal density of subwavelength plasmonic nanoparticles within the cladding layer between the coupling waveguides. Frequency selectivity of the coupling is possible by careful manipulation of the nanoparticle characteristics that govern the effective refractive index of the doped layer that supports plasmonic excitations within a narrow frequency range. The efficient coupling arises from inducing modes within the nanoparticle doped cladding layer of the waveguide in the spectral and spatial vicinities of the selected waveguide modes. Our observations are modeled with the transfer matrix method and corroborated with full-wave simulations.