Multiple higher-order Fano resonances in plasmonic hollow cylindrical nanodimer

Abstract

The optical properties of a nanodimer composed of hollow nanocylinders that are located in a close proximity to each other are investigated. The plasmon modes of the dimer resonator spectrally overlap and induce plasmonic Fano resonances due to destructive interference. For the generation of multiple Fano resonances with large modulation depths and sharp linewidths, several configurations of the dimer nanostructure are analyzed. Different kinds of unique Fano resonances are obtained by changing the polarization of incident light. Moreover, the spectral positions and modulation depths of the higher-order multiple Fano resonances can be flexibly tuned and controlled in the extinction spectrum by varying the geometrical parameters. The proposed resonator has the advantage to exhibit multiple Fano resonances with large modulation depths and offers high values of figure of merit and contrast ratio due to which it can be greatly appropriate for plasmon line shaping, slow light and broadband biosensing applications.