A high throughput supra-wavelength plasmonic bull's eye photon sorter spatially and spectrally multiplexed on silica optical fiber facet.

This paper presents a plasmonic bull's eye consisting of a micron-sized hole and a concentric nano-antenna metallic ring surrounded by periodic circular grooves on a thin gold film. The unique metallic nano-ring imbedded in the supra-wavelength-sized hole acts as an amplifying and filtering component to simultaneously provide a significantly lower spectral noise and a higher power transmission at the resonance wavelength, in comparison to prior sub-wavelength bull's eyes. Systematic numerical analyses based on finite-difference time-domain method were carried out to find the impacts of the structural parameters. Experimentally we integrated three proposed plasmonic structure on a cleaved facet of an optical fiber that can act as a spatially and spectrally multiplexed photon sorter. Transmission characteristics of the proposed devices were characterized in terms of the spectral response and signal to noise ratio. Potential applications of the fiber optic photon sorter were also discussed.