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

In this study, we design a new refractive index sensor based on a metal–insulator–metal waveguide coupled with a notched ring and vertical rectangular resonators. We use the finite element method 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 wide spectrum and narrow spectrum. In the design, the wide spectrum signal is generated by the vertical rectangular resonator, while the narrow spectrum signal is generated by the notched ring resonator. In addition, we varied the structural parameters of the resonators and filled the structure with media of different refractive indices 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.

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Fano Resonance in an Asymmetric MIM Waveguide Structure and Its Application in a Refractive Index Nanosensor

Sensors ◽

10.3390/s19040791 ◽

2019 ◽

Vol 19 (4) ◽

pp. 791 ◽

Cited By ~ 14

Author(s):

Mengmeng Wang ◽

Meng Zhang ◽

Yifei Wang ◽

Ruijuan Zhao ◽

Shubin Yan

Keyword(s):

Refractive Index ◽

Integrated Circuits ◽

Fano Resonance ◽

Structural Parameters ◽

High Sensitivity ◽

Split Ring Resonator ◽

Peak Position ◽

Optical Integrated Circuits ◽

Metal Insulator Metal ◽

Calculation Results

Herein, the design for a tunable plasmonic refractive index nanosensor is presented. The sensor is composed of a metal–insulator–metal waveguide with a baffle and a circular split-ring resonator cavity. Analysis of transmission characteristics of the sensor structures was performed using the finite element method, and the influence of the structure parameters on the sensing characteristics of the sensor is studied in detail. The calculation results show that the structure can realize dual Fano resonance, and the structural parameters of the sensor have different effects on Fano resonance. The peak position and the line shape of the resonance can be adjusted by altering the sensitive parameters. The maximum value of structural sensitivity was found to be 1114.3 nm/RIU, with a figure of merit of 55.71. The results indicate that the proposed structure can be applied to optical integrated circuits, particularly in high sensitivity nanosensors.

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Study on Fano resonance sensing characteristics of double-baffle MDM waveguide coupled disk cavity with absorption material

Modern Physics Letters B ◽

10.1142/s0217984921500652 ◽

2020 ◽

pp. 2150065

Author(s):

Ying Chen ◽

Jinggang Cao ◽

Yangmei Xu ◽

Xinbei Gao ◽

Jinchao Xie

Keyword(s):

Refractive Index ◽

Fano Resonance ◽

Slow Light ◽

Structural Parameters ◽

Destructive Interference ◽

Discrete State ◽

Continuous State ◽

Cavity Structure ◽

Potential Applications ◽

Sensing Characteristics

A metal-dielectric-metal (MDM) waveguide coupled disk cavity structure with bimetallic baffle is proposed, which bases on the transmission characteristics of surface plasmon polaritons (SPPs) in subwavelength structure, and the absorption material InGaAsP is filled in the Fabry–Perot (F-P) cavity and disk cavity. The Fano resonance is an asymmetric spectral line formed by the destructive interference between the wide continuous state generated by the F-P resonator and the narrow discrete state interference generated by the disk cavity. Based on the coupled mode theory, the formation mechanism of the Fano resonance of the structure is qualitatively analyzed. The structure was simulated by finite element method to quantitatively analyze the influence of structural parameters and absorption material InGaAsP on the refractive index sensing characteristics. The proposed sensor yields sensitivity higher than 1360 nm/refractive index unit (RIU) and a figure of merit of [Formula: see text] by optimizing the geometry parameters and filling the absorption material InGaAsP. This structure has potential applications for high integration of nanosensors, slow-light devices, and nano-optical switches.

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Improved Refractive Index-Sensing Performance of Multimode Fano-Resonance-Based Metal-Insulator-Metal Nanostructures

Nanomaterials ◽

10.3390/nano11082097 ◽

2021 ◽

Vol 11 (8) ◽

pp. 2097

Author(s):

Yuan-Fong Chou Chau ◽

Chung-Ting Chou Chao ◽

Siti Zubaidah Binti Haji Jumat ◽

Muhammad Raziq Rahimi Kooh ◽

Roshan Thotagamuge ◽

...

Keyword(s):

Refractive Index ◽

Plasmon Resonance ◽

Fano Resonance ◽

High Sensitivity ◽

Metal Nanostructures ◽

Refractive Index Sensor ◽

Metal Insulator ◽

Wide Range ◽

Metal Insulator Metal ◽

Mode 2

This work proposed a multiple mode Fano resonance-based refractive index sensor with high sensitivity that is a rarely investigated structure. The designed device consists of a metal–insulator–metal (MIM) waveguide with two rectangular stubs side-coupled with an elliptical resonator embedded with an air path in the resonator and several metal defects set in the bus waveguide. We systematically studied three types of sensor structures employing the finite element method. Results show that the surface plasmon mode’s splitting is affected by the geometry of the sensor. We found that the transmittance dips and peaks can dramatically change by adding the dual air stubs, and the light–matter interaction can effectively enhance by embedding an air path in the resonator and the metal defects in the bus waveguide. The double air stubs and an air path contribute to the cavity plasmon resonance, and the metal defects facilitate the gap plasmon resonance in the proposed plasmonic sensor, resulting in remarkable characteristics compared with those of plasmonic sensors. The high sensitivity of 2600 nm/RIU and 1200 nm/RIU can simultaneously achieve in mode 1 and mode 2 of the proposed type 3 structure, which considerably raises the sensitivity by 216.67% for mode 1 and 133.33% for mode 2 compared to its regular counterpart, i.e., type 2 structure. The designed sensing structure can detect the material’s refractive index in a wide range of gas, liquids, and biomaterials (e.g., hemoglobin concentration).

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Sensing Features of the Fano Resonance in an MIM Waveguide Coupled with an Elliptical Ring Resonant Cavity

Applied Sciences ◽

10.3390/app10155096 ◽

2020 ◽

Vol 10 (15) ◽

pp. 5096

Author(s):

Hao Su ◽

Shubin Yan ◽

Xiaoyu Yang ◽

Jing Guo ◽

Jinxi Wang ◽

...

Keyword(s):

Refractive Index ◽

Optical Sensors ◽

Fano Resonance ◽

Resonant Cavity ◽

Refractive Index Sensor ◽

Geometrical Parameters ◽

Elliptical Ring ◽

Metal Insulator Metal ◽

Promising Application ◽

Mim Waveguide

In this article, a novel refractive index sensor composed of a metal–insulator–metal (MIM) waveguide with two rectangular stubs coupled with an elliptical ring resonator is proposed, the geometric parameters of which are controlled at a few hundreds of nanometer size. The transmission feature of the structure was studied by the finite element method based on electronic design automation (EDA) software COMSOL Multiphysics 5.4 (Stockholm, Sweden). The rectangular stub resonator can be thought of as a Fabry–Perot (FP) cavity, which can facilitate the Fano resonance. The simulation results reveal that the structure has a symmetric Lorentzian resonance, as well as an ultrasharp and asymmetrical Fano resonance. By adjusting the geometrical parameters, the sensitivity and figure of merit (FOM) of the structure can be optimized flexibly. After adjustments and optimization, the maximum sensitivity can reach up to 1550 nm/RIU (nanometer/Refractive Index Unit) and its FOM is 43.05. This structure presented in this article also has a promising application in highly integrated medical optical sensors to detect the concentration of hemoglobin and monitor body health.

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Tunable Fano resonance and its application in refractive index sensor

2017 International Conference on Optical Instruments and Technology: Advanced Optical Sensors and Applications ◽

10.1117/12.2296505 ◽

2018 ◽

Author(s):

Xiao b. Ren ◽

kun ren ◽

Ying Zhang

Keyword(s):

Refractive Index ◽

Fano Resonance ◽

Refractive Index Sensor

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A high figure of merit refractive index sensor based on Fano resonance in all-dielectric metasurface

Results in Physics ◽

10.1016/j.rinp.2019.102833 ◽

2020 ◽

Vol 16 ◽

pp. 102833 ◽

Cited By ~ 6

Author(s):

Wei Su ◽

Yimin Ding ◽

Yinlong Luo ◽

Yan Liu

Keyword(s):

Refractive Index ◽

Fano Resonance ◽

Figure Of Merit ◽

Refractive Index Sensor ◽

High Figure ◽

Dielectric Metasurface

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Sensitivity Enhancement of a Concave Shaped Optical Fiber Refractive Index Sensor Covered with Multiple Au Nanowires

Sensors ◽

10.3390/s19194210 ◽

2019 ◽

Vol 19 (19) ◽

pp. 4210 ◽

Cited By ~ 9

Author(s):

Pathak ◽

Rahman ◽

Singh ◽

Kumari

Keyword(s):

Refractive Index ◽

Structural Parameters ◽

Localized Surface Plasmon ◽

Refractive Index Sensor ◽

Au Film ◽

The Core ◽

Enhanced Sensitivity ◽

Guided Mode ◽

Wide Range ◽

Au Nanowires

In the present paper, a new kind of concave shaped refractive index sensor (CSRIS) exploiting localized surface plasmon resonance (LSPR) is proposed and numerically optimized. The LSPR effect between polaritons and the core guided mode of designed CSRIS is used to enhance the sensing performance. The sensor is characterized for two types of sensing structures coated with gold (Au) film and Au nanowires (AuNWs), respectively. The influence of structural parameters such as the distance (D) of the concave shaped channel (CSC) from the core, the diameter of the nanowire (dn) and the size (s) of the CSC are investigated here. In comparison to Au film, the AuNWs are shown to significantly enhance the sensitivity and the performance of the designed sensor. An enhanced sensitivity of 4471 nm/RIU (refractive index unit) is obtained with AuNWs, for a wide range of analytes refractive index (na) varying between 1.33 to 1.38. However, for conventional Au film; the sensitivity of 808.57 nm/RIU is obtained for the same range of analytes.

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Polymer Waveguide Coupled Surface Plasmon Refractive Index Sensor: A Theoretical Study

Photonic Sensors ◽

10.1007/s13320-020-0589-y ◽

2020 ◽

Vol 10 (4) ◽

pp. 353-363

Author(s):

Lanting Ji ◽

Shuqing Yang ◽

Rongna Shi ◽

Yujie Fu ◽

Juan Su ◽

...

Keyword(s):

Refractive Index ◽

Surface Plasmon ◽

Low Cost ◽

High Refractive Index ◽

Waveguide Layer ◽

Polymer Materials ◽

Refractive Index Sensor ◽

Polymer Waveguide ◽

Compact Size ◽

Potential Applications

Abstract A waveguide coupled surface plasmon sensor for detection of liquid with high refractive index (RI) is designed based on polymer materials. The effects of variation of the thickness of the Au film, polymethyl methacrylate (PMMA) buffer, and waveguide layer on the sensing performance of the waveguide are comprehensively investigated by using the finite difference method. Numerical simulations show that a thinner gold film gives rise to a more sensitive structure, while the variation of the thickness of the PMMA buffer and waveguide layer has a little effect on the sensitivity. For liquid with high RI, the sensitivity of the sensor increases significantly. When RI of liquid to be measured increases from 1.45 to 1.52, the sensitivity is as high as 4518.14nm/RIU, and a high figure of merit of 114.07 is obtained. The waveguide coupled surface plasmon RI sensor shows potential applications in the fields of environment, industry, and agriculture sensing with the merits of compact size, low cost, and high integration density.

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