Refractive Index Sensor Based on a Metal–Insulator–Metal Waveguide Coupled with a Symmetric Structure

Abstract

In this study, a new refractive index sensor based on a metal–insulator–metal waveguide coupled with a notched ring resonator and stub is designed. The finite element method is used to study the propagation characteristics of the sensor. According to the calculation results, the transmission spectrum exhibits a typical Fano resonance shape. The phenomenon of Fano resonance is caused by the coupling between the broadband spectrum and narrowband spectrum. In the design, the broadband spectrum signal is generated by the stub, while the narrowband spectrum signal is generated by the notched ring resonator. In addition, the structural parameters of the resonators and the structure filled with media of different refractive indices are varied to study the sensing properties. The maximum achieved sensitivity of the sensor reached 1071.4 nm/RIU. The results reveal potential applications of the coupled system in the field of sensors.

Plasmonic Filter and Demultiplexer Based on Square Ring Resonator

“…Since the FWHM is 67 nm, the FOM is approximately 20/RIU. This value is better than those reported in some recent works based on MIM structures [15][16][17][18][19].…”

“…Since the FWHM is 67 nm, the FOM is approximately 20/RIU. This value is better than those reported in some recent works based on MIM structures [15][16][17][18][19]. A dynamically tunable device can also be realized based on such a filter filled with nonlinear optical materials, as proposed in Figure 4c.…”

“…Therefore, MIM-based plasmonic devices will play an important role in future PICs. Recently, many kinds of plasmonic devices utilizing the MIM structure have been introduced, such as filter [4][5][6], demultiplexer [7][8][9], switch [10][11][12][13], and sensor devices [14][15][16][17][18][19].…”

Dual-Mode On-to-Off Modulation of Plasmon-Induced Transparency and Coupling Effect in Patterned Graphene-Based Terahertz Metasurface

“…At present, surface plasmon polaritons (SPPs), as a carrier for transmitting information and energy, have become a research hotspot in the sub-wavelength optics. Generally, they are produced by the interaction between the photons in the incident light field and the electrons on the metal or insulator surface [1,2]. The SPPs facilitate the development and manufacture of highly integrated optics and photonic circuits owing to their unique optical properties.…”

Critical-Angle Differential Refractometry of Lossy Media: A Theoretical Study and Practical Design Issues

“…Refractive index sensors are intensely investigated for numerous biomedical [1][2][3], chemical [4,5] and industrial [6,7] applications. An indicative yet far from exhaustive list of sensing mechanisms relies on plasmonic [8][9][10][11], photonic crystal [12][13][14][15], micro-cavity [16][17][18][19], optical fiber [20][21][22][23] and wave-guide [24][25][26][27] configurations. Associated with Fresnel reflectance properties at planar interfaces, differential refractometry offers an alternative path to sensing refractive index changes, by exploitation of interference [28], deflection [29] or (more relevant to the present work) critical-angle [30][31][32][33][34][35] effects.…”