Tuning Multiple Fano Resonances for On-Chip Sensors in a Plasmonic System.

Shilin Yu,Jianguo Yu,Tonggang Zhao,Dafa Pan

doi:10.3390/s19071559

Shilin Yu, Jianguo Yu + Show 2 more

Open Access

https://doi.org/10.3390/s19071559

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Abstract

This paper proposed a plasmonic resonator system, consisting of a metal-insulator-metal structure and two stubs, and a Fano resonance arose in its transmittance, which resulted from the coupling between the two stubs. On the basis of the proposed structure, a circle and a ring cavity are separately added above the stubs to create different coupled plasmonic structures, providing triple and quadruple Fano resonances, respectively. Additionally, by adjusting the geometric parameters of the system, multiple Fano Resonances obtained can be tuned. The proposed structure can be served as a high efficient refractive index sensor, yielding a sensitivity of 2000 nm/RIU and figure of merit (FOM) of and performing better than most of the similar structures. It is believed that the proposed structure may support substantial applications for on-chip sensors, slow light and nonlinear devices in highly integrated photonic circuits.

Highlights

Fano resonance arises from the coupling and interference between a discrete state and a continuous state [1,2]
Fano resonance is investigated in metallic nanostructure since the perfect trait of avoiding the diffraction limit of light [1] owned by Surface plasmon polaritons (SPPs)
It is believed that the proposed structure may support substantial applications for nano-sensor, slow light and nonlinear devices in highly integrated photonic circuits

Summary

Introduction

Fano resonance arises from the coupling and interference between a discrete state and a continuous state [1,2]. Chao Li et al designed Multiple Fano Resonances based on plasmonic resonator system with end-coupled cavities for high-performance nanosensor [22] with a sensitivity of 1100 nm/RIU and a figure of merit (FOM) about 2.73 × 104 ; YY. Zhang et al proposed a triple Fano resonance structure [8] and applied to nanosensor with a sensitivity of 800 nm/RIU and maximum FOM about. Our previous work [13] proposed a multiple Fano resonances system and served as a nanosensor, yielding a sensitivity of 2000 nm/RIU and figure of merit (FOM) about 3000. Applied to the refractive index sensor, the proposed structure shows high performance with a sensitivity of 2000 nm/RIU and figure of merit(FOM) of 4.05 × 104. It is believed that the proposed structure may support substantial applications for nano-sensor, slow light and nonlinear devices in highly integrated photonic circuits

Basic Model and Theoretical Analysis

A Way to Induce Multiple Fano Resonances

Adding

Refractive Index Sensing Based on the Multiple Fano Resonances

Slow Light Effects of the Multiple Fano Resonances

Conclusions