High-Sensitivity Refractive Index Sensors Using Coherent Perfect Absorption on Graphene in the Vis-NIR Region

2019 ◽  
Vol 2 (5) ◽  
pp. 3231-3237 ◽  
Author(s):  
Chawei Li ◽  
Jinlin Qiu ◽  
Jun-Yu Ou ◽  
Qing Huo Liu ◽  
Jinfeng Zhu
Keyword(s):  
Refractive Index ◽  
High Sensitivity ◽  
Perfect Absorption ◽  
Coherent Perfect Absorption ◽  
Refractive Index Sensors

Strain, torsion and refractive index sensors based on helical long period fibre grating inscribed in small-core fibre for structural condition monitoring

2021 ◽  
Vol 24 (6) ◽  
pp. 1248-1255
Author(s):  
Cailing Fu ◽  
Yi-Qing Ni ◽  
Tong Sun ◽  
Yiping Wang ◽  
Siqi Ding ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Sensitivity ◽  
Single Mode ◽  
Structural Condition ◽  
Core Diameter ◽  
Small Core ◽  
Long Period ◽  
Sensing Applications ◽  
Core Fibre ◽  
Refractive Index Sensors

This study is intended to develop long period fibre grating sensors for potential applications in environmental and durability monitoring of coastal structures. High-quality helical long period fibre gratings (HLPFGs) are inscribed in different types of small-core single mode fibre (SMF) by use of hydrogen-oxygen flame heating technique. A detailed investigation of the effect of core diameter on their transmission spectrum and optimum length of the HLPFG has been pursued. A longer length is required to achieve the same coupling attenuation in a smaller-core SMF than that of a larger-core fibre. The strain, torsion and refractive index (RI) properties of the HLPFG is investigated experimentally to develop a high-sensitivity sensor. The experimental results show that the strain sensitivity could be enhanced by means of employing a larger-core diameter SMF. Moreover, the HLFPGs are also sensitive to the torsion and external RI. Hence, such HLFPGs have great potential for sensing applications.

scholarly journals Achievements in the development of plasmonic waveguide sensors for measuring the refractive index

2020 ◽  
Vol 44 (3) ◽  
pp. 295-318 ◽  
Author(s):  
N.L. Kazanskiy ◽  
M.A. Butt ◽  
S.A. Degtyarev ◽  
S.N. Khonina
Keyword(s):  
Refractive Index ◽  
Optical Sensors ◽  
Spectral Characteristics ◽  
High Sensitivity ◽  
Fluorescent Labeling ◽  
Silicon Waveguides ◽  
Food Industries ◽  
Specific Distribution ◽  
Metal Insulator Metal ◽  
Refractive Index Sensors

Optical sensors are widely used in the biomedical, chemical and food industries. They provide high sensitivity to changes in the refractive index of the environment due to a specific distribution of resonances across the field. The sensitivity of the sensor is highly dependent on its material and structure. In this review, we focused on the analysis of silicon waveguides as a promising component for optical sensor miniaturization, and plasmon refractive index sensors without fluorescent labeling. We presented the latest developments of special types of plasmon structures, such as metal-insulator-metal waveguides, and their application in refractive index sensors. We analyzed numerous types of plasmon waveguides, their geometry, materials and manufacturing processes, as well as possible energy losses. A discussion of the spectral characteristics of recently proposed refractive index sensors, with an emphasis on their sensitivity and quality indicators, is an important part of the review.

scholarly journals Metal-insulator-metal nanoresonators – strongly confined modes for high surface sensitivity

Nanophotonics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1547-1552
Author(s):  
George Duffett ◽  
Ralph Wirth ◽  
Mathieu Rayer ◽  
Emiliano R. Martins ◽  
Thomas F. Krauss
Keyword(s):  
Refractive Index ◽  
High Surface ◽  
High Sensitivity ◽  
Metal Insulator ◽  
Surface Sensitivity ◽  
Novel Approach ◽  
Metal Insulator Metal ◽  
Spatially Extended ◽  
Extended Surface ◽  
Refractive Index Sensors

AbstractPhotonic and plasmonic refractive index sensors are able to detect increasingly smaller refractive index changes and concentrations of clinically relevant substances. They typically exploit optical resonances and aim to maximise the field overlap with the analyte in order to achieve high sensitivity. Correspondingly, they operate on the basis of maximizing the bulk sensitivity, which favours spatially extended modes. We note that this strategy, counter-intuitively, is not necessarily suitable for detecting biomolecules and one should focus on the surface sensitivity instead. Here, we show that by confining light tightly in metal-insulator-metal (MIM) nanoresonators, the surface sensitivity is significantly increased despite a clear decrease in bulk sensitivity. In particular, we experimentally show the operation of third order MIM resonators which support both extended surface plasmon polariton (SPP) modes and localized MIM modes. We are able to demonstrate that the MIM mode has a sensitivity of 55 nm/RIU to a 10 nm layer, which is approximately twice as high as that of the SPP mode. Overall, our work emphasizes the importance of the surface sensitivity over the more commonly used bulk sensitivity and it shows a novel approach for improving it. These insights are highly relevant for the design of next generation optical biosensors.

Independently tunable dual resonant dip refractive index sensor based on metal-insulator-metal waveguide with Q-shaped resonant cavity

2022 ◽  
Author(s):  
Haowen Chen ◽  
Yunping Qi ◽  
Jinghui Ding ◽  
Yujiao Yuan ◽  
Zhenting Tian ◽  
...  
Keyword(s):  
Refractive Index ◽  
Resonant Cavity ◽  
Fdtd Method ◽  
High Sensitivity ◽  
Refractive Index Sensor ◽  
Metal Insulator ◽  
Metal Waveguide ◽  
Metal Insulator Metal ◽  
Simulation Results ◽  
Refractive Index Sensors

Abstract A plasmonic resonator system consisting of a metal-insulator-metal waveguide and a Q-shaped resonant cavity is proposed in this paper. The transmission properties of surface plasmon polaritons in this structure are investigated using the finite difference in time domain (FDTD) method, and the simulation results contain two resonant dips. And the physical mechanism is studied by the multimode interference coupled mode theory (MICMT), the theoretical results are in highly consistent with the simulation results. Furthermore, the parameters of the Q-shaped cavity can be controlled to adjust two dips respectively. The refractive index sensor with a sensitivity of 1578nm/RIU and figure of merit (FOM) of 175, performs better than most of the similar structures. Therefore, the results of the study are instructive for the design and application of high sensitivity nanoscale refractive index sensors.

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