A MIM Waveguide Structure of a High-Performance Refractive Index and Temperature Sensor Based on Fano Resonance

Pengwei Liu,Shubin Yan,Yifeng Ren,Xiushan Wu,Ertian Hua,Xiaoyu Zhang,Tingsong Li,Lifang Shen

doi:10.3390/app112210629

Abstract

A plasmonic refractive index nanosensor structure consisting of a metal-insulator-metal (MIM) waveguide with two symmetrical rectangle baffles coupled with a connected-concentric-double rings resonator (CCDRR) is presented. In this study, its transmission characteristics were investigated using the finite element method (FEM). The consequences, studied via simulation, revealed that the transmission spectrum of the system presents a sharp asymmetric Fano profile due to the destructive interference between the wide-band mode of two rectangle baffles on the bus waveguide and the narrow-band mode of the CCDRR. The effects of the geometric parameters of the structure on the transmission characteristics were investigated comprehensively. A sensitivity of 2260 nm/RIU and figure of merit (FOM) of 56.5 were the best levels of performance that the designed structure could achieve. In addition, the system could act as a sensor for use for temperature sensing, with a sensitivity that could reach 1.48 nm/°C. The designed structure advances with technology with new detection positions and has good application prospects in other high-sensitivity nanosensor fields, for example, acting as a biosensor to detect the hemoglobin level in the blood.

Highlights

Surface plasmon polaritons (SPPs) is a phenomenon whereby a metal surface charges when interacting with a light wave electromagnetic field; they oscillate collectively, so that the electromagnetic field is limited to a small range and is enhanced [1]
Fano resonance generally comes from the destructive interference between the wide-band mode and the narrow-band mode in plasmon resonance, which has a small radiation loss, a narrow full width at half maximum (FWHM), and an asymmetric spectral line shape [10,11]
Yang et al [22] designed a coupling structure with a double-gap ring cavity and MIM waveguides with two triangular baffles with a sensitivity of 1500 nm/RIU and figure of merit (FOM) of 65.2

Summary

Introduction

Surface plasmon polaritons (SPPs) is a phenomenon whereby a metal surface charges when interacting with a light wave electromagnetic field; they oscillate collectively, so that the electromagnetic field is limited to a small range and is enhanced [1]. Yang et al [22] designed a coupling structure with a double-gap ring cavity and MIM waveguides with two triangular baffles with a sensitivity of 1500 nm/RIU and figure of merit (FOM) of 65.2.

Results

Conclusion