Dual-Fano resonances and sensing properties in the crossed ring-shaped metasurface
Zhihui He, Chunjiang Li, Wei Cui, Weiwei Xue, Zhenxiong Li, Lihui Pu, Jiaojiao Feng, Xintao Xiao, Xuyang Wang, Yajie Liu, Qirui Zou, Yufei Yao, Yixuan Niu, Mengyuan Wang
Abstract
We study dual-Fano resonances and its sensing properties in a crossed ring-shaped metasurface by use of the finite-different time-domain (FDTD) simulation. The results show that the dual-Fano resonances in the proposed crossed ring-shaped metasurface are caused by the interaction among three local surface plasmon resonances (LSPRs), and spectra of the dual-Fano resonances can be tuned by the radius of the circular ring (CR) nanostructure, the distance between the center of the two CRs in x direction, and the polarization of the incident light. Interestingly, single Fano resonance splits into dual-Fano resonances in the case of the asymmetric ring structure arrangement or the non-y-axis polarized incident or the distance d < 120 nm. Moreover, we can also find that the sensitivity for the refractive index in the proposed crossed ring-shaped metasurface can reach up to 1010 nm/RIU and 1300 nm/RIU at Fano resonance peak 1 and Fano resonance peak 2, respectively. These results may play an important role for designing high sensitive plasmonic sensors.