High-quality Fano resonances and multispectral perfect absorption in mushroom-type dielectric metamaterials with a silver nanofilm

¹ School of Electronic Science and Applied Physics, Hefei University of Technology - Hefei, Anhui 230009, China
² School of Physics and Electronics, Hunan University - Changsha 410082, China
³ School of Physics and Electronics Science, Hunan University of Science and Technology - Xiangtan, 411201, China

^(a) qinm@hfut.edu.cn

Received: 21 January 2021
Accepted: 1 March 2021

Abstract

Dielectric metamaterials with high refractive index have drawn intensive attention owing to their advantages of confinement and guiding of light in practical photonic devices. Here, we propose a hybrid nanostructure, consisting of mushroom-type dielectric nanoarrays and plasmonic nanofilms, towards the goal of achieving multispectral perfect absorption of light and high-quality Fano resonance. Our studies reveal that the proposed structure indeed possesses the expected properties of light harvest and Fano resonance, which is induced by the coupling between plasmonic and Mie-type resonant modes. Furthermore, the resonant field distributions inside the nanostructure and the effects of modifying the parameters of dielectric nanoarrays on resonant modes are systematically investigated. Our findings of nearly total absorption in silicon and high-quality sensing of the combined system will greatly benefit the applications of solar energy transition and sensors.