Fano Resonances Generated in a Single Dielectric Homogeneous Nanoparticle with High Structural Symmetry

Abstract

Fano resonances in plasmonic nanostructures suppress radiative losses effectively, but nonradiative Ohmic losses limit the performance of many important applications. In addition, it is hard to generate strong Fano resonances in a single plasmonic homogeneous nanoparticle with high structural symmetry. Dielectric nanostructures offer a potential solution to the above issues. There are various subradiant hybrid modes in a single dielectric nanoparticle, making it possible to generate Fano resonances. This study shows that due to the excitation of the subradiant hybrid EH12δ mode a strong Fano resonance is generated in a single silicon nanodisk. Higher-order subradiant hybrid modes (EH13δ and EH14δ) are excited by manipulating the disk radius, and multiple Fano resonances arise in spectra. These optical responses are not dependent on a retardation effect, and strong Fano resonances are generated even for a very thin disk. One can get similar results in a single dielectric triangle, square, or rectangle nanoplate. The simple geometry and high structural symmetry make these dielectric nanoparticles promising for practical implementations in biosensing and optoelectronics.