Highly Sensitive Refractive Index Sensor Based on All-Dielectric Defective Nanotetramer Metastructure
SUN Qinghe
FAN Xinye
FANG Wenjing
CAO Shuangshuang
WANG Dandan
NIU Huijuan
TAO Jifang
Abstract：In this paper,an all-dielectric nanotetramer metastructure with high sensitivity is proposed and investigated.The structure consists of a periodic array of defective cylinders located on a SiO2 substrate.The transmission spectrum and electromagnetic field distribution of the asymmetric all-dielectric meta-structure are numerically analyzed by using the finite-difference time-domain(FDTD)method.Based on the bound states in continuum(BIC)theory,the symmetry is broken by introducing in-plane cylindrical defects,and multiple Fano resonances are excited in the near-infrared range with a maximum Q-factor of 1 277 and a modulation depth close to 100％.Combined with the electromagnetic field distribution charac-teristics,the resonance modes of the five Fano resonance peaks are analyzed,which are TD(toroidal di-pole),MQ(magnetic quadrupole),MD(magnetic dipole),MDs,and TD.Simulation results show that the structure has good sensing performance with a sensitivity of 826 nm/RIU and the Figure of merit(FOM)of 898 RIU-1.The proposed structure can be widely used in environmental sensing,biological sensing and nonlinear optics due to its high sensitivity and high Q-factor.
Keywords：all-dielectricmetastructurehigh sensitivitybound states in the continuum
Publication Date：2024-10-28
Online Publishing Date：2026-08-28(First online date of this platform, not the publication date of the document)
Pages：9( 68-75,122 )