Fano effects induced by toroidal resonances in hybrid plasmonic-dielectric nanostructures

Fano resonance is ubiquitous in plasmonic structures, resulting from interference between a bright mode and a dark mode. Toroidal dipole resonances, which are in general of high-Q, represent an important response in ”toroidal metamaterials.” We study the Fano resonance effect arising from the toroidal resonances in various plasmonic-dielectric nanostructures. It is shown that extinction, transmission, and photoluminescence can feature the Fano interaction which is important for the macroscopic properties, enabling efficient design of unique photonic nanostructures and metamaterials.