High Sensitivity Plasmonic Sensor Based on Fano Resonance with Inverted U-Shaped Resonator

Sensors (Basel). 2021 Feb 7;21(4):1164. doi: 10.3390/s21041164.

Authors

Gongli Xiao¹, Yanping Xu¹, Hongyan Yang^{2

3}, Zetao Ou¹, Jianyun Chen¹, Haiou Li¹, Xingpeng Liu¹, Lizhen Zeng⁴, Jianqing Li⁵

Affiliations

¹ Guangxi Key Laboratory of Precision Navigation Technology and Application, Guilin University of Electronic Technology, Guilin 541004, China.
² Guangxi Key Laboratory of Automatic Detecting Technology and Instruments, Guilin University of Electronic Technology, Guilin 541004, China.
³ School of Electronic Engineering and Automation, Guilin University of Electronic Technology, Guilin 541004, China.
⁴ Graduate School, Guilin University of Electronic Technology, Guilin 541004, China.
⁵ Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology, Foshan University, Foshan 528225, China.

Abstract

Herein, we propose a tunable plasmonic sensor with Fano resonators in an inverted U-shaped resonator. By manipulating the sharp asymmetric Fano resonance peaks, a high-sensitivity refractive index sensor can be realized. Using the multimode interference coupled-mode theory and the finite element method, we numerically simulate the influences of geometrical parameters on the plasmonic sensor. Optimizing the structure parameters, we can achieve a high plasmonic sensor with the maximum sensitivity for 840 nm/RIUand figure of merit for 3.9 × 10⁵. The research results provide a reliable theoretical basis for designing high sensitivity to the next generation plasmonic nanosensor.

Keywords: Fano resonance; finite element method; metal-dielectric-metal; plasmonic nanosensor.