title: Refractive Index Sensor Based on Fano Resonances in Metal-Insulator-Metal Waveguides Coupled with Resonators.
abstract: A surface plasmon polariton refractive index sensor based on Fano resonances in metal-insulator-metal (MIM) waveguides coupled with rectangular and ring resonators is proposed and numerically investigated using a finite element method. Fano resonances are observed in the transmission spectra, which result from the coupling between the narrow-band spectral response in the ring resonator and the broadband spectral response in the rectangular resonator. Results are analyzed using coupled-mode theory based on transmission line theory. The coupled mode theory is employed to explain the Fano resonance effect, and the analytical result is in good agreement with the simulation result. The results show that with an increase in the refractive index of the fill dielectric material in the slot of the system, the Fano resonance peak exhibits a remarkable red shift, and the highest value of sensitivity (S) is 1125 nm/RIU, RIU means refractive index unit. Furthermore, the coupled MIM waveguide structure can be integrated with other photonic devices at the chip scale. The results can provide a guide for future applications of this structure.
authors.affiliation: Science and Technology on Electronic Test and Measurement Laboratory, North University of China, No. 3 Xueyuan Road, Taiyuan 030051, China. Yue_Tang_1103@163.com.
authors.forename: Yue
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Science and Technology on Electronic Test and Measurement Laboratory, North University of China, No. 3 Xueyuan Road, Taiyuan 030051, China. zdzhang@nuc.edu.cn.
authors.forename: Zhidong
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Science and Technology on Electronic Test and Measurement Laboratory, North University of China, No. 3 Xueyuan Road, Taiyuan 030051, China. bingruiwang_281@163.com.
authors.forename: Ruibing
authors.initials: R
authors.lastname: Wang
authors.affiliation: Ghent University Global Campus, Department of Applied Analytical and Physical Chemistry, Faculty of Bioscience Engineering, 119 Songdo Munhwa-ro, Yeonsu-Gu, Incheon 406-840, Korea. zhenyin.hai@ugent.be.
authors.forename: Zhenyin
authors.initials: Z
authors.lastname: Hai
authors.affiliation: Science and Technology on Electronic Test and Measurement Laboratory, North University of China, No. 3 Xueyuan Road, Taiyuan 030051, China. xuechenyang@nuc.edu.cn.
authors.forename: Chenyang
authors.initials: C
authors.lastname: Xue
authors.affiliation: Science and Technology on Electronic Test and Measurement Laboratory, North University of China, No. 3 Xueyuan Road, Taiyuan 030051, China. wdzhang@nuc.edu.cn.
authors.forename: Wendong
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Science and Technology on Electronic Test and Measurement Laboratory, North University of China, No. 3 Xueyuan Road, Taiyuan 030051, China. shubin_yan@nuc.edu.cn.
authors.forename: Shubin
authors.initials: S
authors.lastname: Yan
keywords: Fano resonance; coupled-mode theory; finite element method; plasmonic refractive index sensor