scholarly journals Narrowband Perfect Absorber Based on Dielectric-Metal Metasurface for Surface-Enhanced Infrared Sensing

2020 ◽  
Vol 10 (7) ◽  
pp. 2295 ◽  
Author(s):  
Guilian Lan ◽  
Zhongxie Jin ◽  
Jinpeng Nong ◽  
Peng Luo ◽  
Caicheng Guo ◽  
...  

We proposed a narrowband perfect absorber that was based on dielectric-metal metasurface for wide-band surface-enhanced infrared sensing. It is found that the narrowband perfect absorber can generate the hybrid guided modes with high quality-factor at infrared frequencies, which make the absorber highly sensitive to the surrounded analyte. Moreover, tuning the incident angle can actively modulate the resonant wavelength of absorber. Such an absorber with excellent features is employed to realize both refractive index sensing and infrared vibrational fingerprint sensing on a single substrate. It is demonstrated that a refractive index sensitivity of 1800 nm/RIU and figure of merit of 62 RIU−1 can be obtained as the refractive index sensor. While, as a surface enhanced infrared absorption spectroscopy substrate, two closed vibrational modes of analyte with nanometer thick layers can be effectively identified and selectively detected with 50-folds enhancement by actively tuning the incident angle without any change in the structural parameters (periodicity, width, height, and refractive index of the grating) of the device after fabricating. Our study offers a promising approach for designing high-performance surface-enhanced infrared optical sensors in the infrared region.

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1552
Author(s):  
Bin Liu ◽  
Pinghui Wu ◽  
Hongyang Zhu ◽  
Li Lv

This paper proposes a perfect metamaterial absorber based on a dielectric−dielectric−metal structure, which realizes ultra-narrowband dual-band absorption in the near-infrared band. The maximum Q factor is 484. The physical mechanism that causes resonance is hybrid coupling between magnetic polaritons resonance and plasmon resonance. At the same time, the research results show that the intensity of magnetic polaritons resonance is much greater than the intensity of the plasmon resonance. By changing the structural parameters and the incident angle of the light source, it is proven that the absorber is tunable, and the working angle tolerance is 15°. In addition, the sensitivity and figure of merit when used as a refractive index sensor are also analyzed. This design provides a new idea for the design of high-Q optical devices, which can be applied to photon detection, spectral sensing, and other high-Q multispectral fields.


Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 789
Author(s):  
Chieh-Ting Lin ◽  
Ta-Jen Yen ◽  
Tsung-Yu Huang

Simultaneous surface enhanced infrared absorption (SEIRA) with Fano resonance and refractive index (RI) sensing are proposed via a split-ring-resonator-based metamaterial perfect absorber (MPA) to detect polyvinyl chloride (PVC), a commonly used polymer but one that was recently prohibited in many areas such as Europe. This bifunctional sensor could provide a label-free and qualitative PVC detection through SEIRA coupled to the vibration mode and a quantitative measurement through RI sensing. To design the MPA, the main operating frequency is targeted at 615 cm−1 for C-Cl bond of PVC. Transition from a reflectance dip to a peak, i.e., Fano resonance was observed at y polarization in both simulation and experiments, evidencing the existence of PVC. On the other hand, to test the RI sensing ability of the MPA, different RI (from 1 to 1.5) of analytes and different thicknesses (from 109 to 1050 nm) of polymethyl methacrylate (PMMA) were applied to the MPA in simulation and experiments, respectively. The simulated sensitivities are 4045 and 2361 nm/RIU for the first and third modes of the MPA, respectively, while the measured sensitivities based on PMMA are 3713 and 1694 nm/RIU. Overall, the detection limit of PVC could be down to 0.5% in experiments, which outweighs the current measurement limit of 10% through infrared absorption measurement.


2015 ◽  
Vol 29 (33) ◽  
pp. 1550218 ◽  
Author(s):  
Tiesheng Wu ◽  
Yumin Liu ◽  
Zhongyuan Yu ◽  
Han Ye ◽  
Changgan Shu ◽  
...  

A novel surface plasmon polaritons (SPPs) refractive index sensor based on a single defect nanocavity coupled with a metal–insulator–metal (MIM) waveguide is proposed and numerically simulated by using the finite difference time domain (FDTD) method with perfectly matched layer absorbing boundary condition. It is found that the defect structure can realize two Fano resonances and these two Fano resonances originate from two different mechanisms. The results demonstrate the liner correlation between the resonance wavelengths of the device and the refractive index of the material under sensing. Through the optimization of structural parameters, we achieve a theoretical value of the refractive index sensitivity as high as 1800.4 nmRIU[Formula: see text]. It could be utilized to develop ultra-compact nanodevice for high-resolution biological sensing.


2021 ◽  
Author(s):  
jun zhu ◽  
Yihong Ren

Abstract The scattering and absorption characteristics of light by spherical particles are often analysed based on the classical Mie scattering theory.In this paper,we study refractive index sensor of multi-mode based on the Mie scattering and its extension theories. Based on the Mie scattering theory, the light extinction, scattering, absorption cross-section, and absorption efficiency associated with the spherical particle can be calculated.The structure that we design has a long wavelength possesses a higher power than that with a short wavelength.Also,the structural parameters induces a red-shift in the resonance spectrum. Lastly,the results of multi-mode are obtained: the transmittance of modes 1, 2, and 3 vary within the ranges 0.43–0.67, 0.61–0.46, and 0.26–0.5, respectively; the figures of merit of modes 1, 2, and 3 can reach as high as 12, 27.7, and 3.8, respectively; the refractive index sensitivity can reach as high as and . As indicated by these findings, the proposed structure can significantly improve the transmission characteristics of nanodevices. Such a structure holds significant potential for application in the field of on-chip plasma sensing and optical communication.


2021 ◽  
Vol 8 ◽  
Author(s):  
Yanping Yin ◽  
Jin Zhu ◽  
Zaoji Wang ◽  
Guojun Ma ◽  
Huining Yuan ◽  
...  

In recent years, the plasma gap resonance maintained by metal-film-coupled nanostructures has attracted extensive attention. This mainly originates from its flexible control of the spectral response and significantly enhanced field strength at the nanoparticle–film junction. In the present study, the tunability of local surface plasmon resonances (LSPRs) of nanorods coupled to a gold film is studied theoretically. To this end, the plasmonic resonances in the nanostructure of individual silver nanorod–gold film (AgNR-film) with different parameters are investigated. Obtained results show that the refractive index sensitivity (S) of nanostructures to the environment increases as the aspect ratio (Ar) of nanostructures increase. It is found that when the aspect ratio (Ar) is set to 3.5, the figure of merit (FOM) is the highest. Moreover, the variation in the gap distances of the nanorod monomer–gold film, electric field distribution of nanorods dimer, and the corresponding impact on the gold film are studied. It is concluded that the gap size of nanostructures has an exponential correlation with the resonance wavelength. Considering the remarkable influence of the gap size and the surrounding medium environment on the spectral shift of AgNR-film nanostructures, potential applications of the structure as a refractive index sensor and biomolecule measurement are proposed.


2020 ◽  
Vol 10 (15) ◽  
pp. 5096
Author(s):  
Hao Su ◽  
Shubin Yan ◽  
Xiaoyu Yang ◽  
Jing Guo ◽  
Jinxi Wang ◽  
...  

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.


Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4210 ◽  
Author(s):  
Pathak ◽  
Rahman ◽  
Singh ◽  
Kumari

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.


Author(s):  
Shidi Liu ◽  
Tianyu Yang ◽  
Liang Zhang ◽  
Ming Tian ◽  
Yuming Dong

Abstract A robust and simple mid-infrared hollow-core anti-resonant fiber (ARF) based refractive index (RI) sensor with an intensity demodulation method is presented and analyzed for monitoring liquid analytes. The ARF allows liquid analytes to flow through its hollow area for detection. To obtain ideal sensing performance, an epsilon negative (ENG) material is introduced into the selected anti-resonant tube. With the high absorption of the ENG material, only one fundamental mode is available for detection and is sensitive to the RI variation of analytes. Moreover, the effects of structural parameters on the sensing performances are discussed and analyzed to further understand the mechanism and optimization. The final result shows that the ARF sensor can exhibit a high sensitivity of -372.58 dB/RIU at a fixed wavelength within a broad RI range from 1.33 to 1.45, which covers most liquid analytes. It is a promising candidate for chemical and environmental analysis. Additionally, it has the potential for deep research to feed diverse applications.


Author(s):  
Xianglong Wu ◽  
Ying Zheng ◽  
Yao Luo ◽  
Jianguo Zhang ◽  
Zao Yi ◽  
...  

A four-band terahertz tunable narrow-band perfect absorber based on Bulk Dirac semi-metallic (BDS) metamaterial with microstructure is designed. The three-layer structure of this absorber from top to bottom is the...


Author(s):  
Monika Kiroriwal ◽  
Poonam Singal

Surface plasmon resonance (SPR)-based single-core photonic crystal fiber (PCF) biosensor is investigated with external gold coating. All the geometrical parameters such as a gold layer, an analyte layer, a lattice period and cladding air holes are optimized to enhance the sensing ability of the sensor by introducing the finite element method. The designed sensor is able to achieve the highest amplitude sensitivity (AS) of 2258.95 RIU[Formula: see text] with an acceptable refractive index sensitivity (RIS) of 6000 nm/RIU over the analyte refractive index (ARI) span of 1.31–1.40. This sensor can detect a slight index alteration in the sensing medium using a resolution of [Formula: see text] and a high figure of merit (FOM) of 79.01. With the enhanced modal behavior with simple geometry, the resulting sensor can be suitable for real-time monitoring in biological, biochemical and bio-imaging applications.


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