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Optical Fiber Cladding SPR Sensor Based on Core-Shift Welding Technology
摘要： The typical structure of an optical fiber surface plasmon resonance (SPR) sensor, which has been widely investigated, is to produce the SPR phenomenon by the transmission of light in a fiber core. The traditional method is to peel off the fiber cladding by complex methods such as corrosion, polishing, and grinding. In this paper, the transmitted light of a single-mode fiber is injected into three kinds of fiber cladding by core-shift welding technology to obtain the evanescent field directly between the cladding and the air interface and to build the Kretschmann structure by plating with a 50-nm gold film. The SPR sensing phenomenon is realized in three kinds of fiber cladding of a single-mode fiber, a graded-index multimode fiber, and a step-index multimode fiber. For the step-index multimode fiber cladding SPR sensor, all the light field energy is coupled to the cladding, leading to no light field in the fiber core, the deepest resonance valley, and the narrowest full width at half maximum. The single-mode fiber cladding SPR sensor has the highest sensitivity, and the mean sensitivity of the probe reaches 2538 nm/RIU (refractive index unit) after parameter optimization.
关键词： fiber cladding SPR,surface plasmon resonance
更新于2025-11-28 14:24:03
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Effects of TiO2 on the performance of silver coated on side-polished optical fiber for alcohol sensing applications
摘要： This work reports the experimental and numerical investigations on the effect of titanium oxide (TiO2) integrated on the optical fiber silver (Ag) surface plasmon resonance (SPR) sensors. In this paper, the numerical simulation is also analyzed using the finite element method (FEM) which shows good agreement. Results are compared with the experimental findings, focusing on the SPR phenomena for refractive index sensing using side-polished optical fiber, where the characteristics of the Ag layer with the integration of TiO2 are optimized. The essential parameters include the thickness of Ag namely 20 nm, 30 nm and 40 nm for optimization studies of SPR properties. TiO2 was then coated on the Ag thin layer to sense isopropanol at different concentration. It is shown that the combination of a 30 nm thickness of Ag layer with a dielectric TiO2 improves sensor performance in terms of sensitivity reading of 268 nm/RIU with a detection limit of 0.012. The main interest is to develop the device with cost effective, ease fabrication and less cumbersome of sensors using TiO2 which one of an alternative material to defeat the oxidation process and avoid charge recombination. If the sensitivity increases at a higher wavelength, it indicates that the TiO2 holds great potential in photonic applications.
关键词： Fiber Optic Alcohol Sensor,Surface plasmon resonance (SPR),Finite element method (FEM)
更新于2025-11-28 14:23:57
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Construction of a high-performance photocatalytic fuel cell (PFC) based on plasmonic silver modified Cr-BiOCl nanosheets for simultaneous electricity production and pollutant removal
摘要： The development of high-performance photocatalytic fuel cell (PFC) is seriously hampered by the poor light utilization rate and low charge carriers transfer efficiency. Herein, we have experimentally obtained the plasmonic Ag modified Cr-BiOCl (Cr-BOC/Ag) with high visible light photocatalytic activity and provided direct evidence for the substantially enhanced catalytic activity in metal-semiconductor photocatalysts. The experimental results revealed that the Cr doping and Ag modification could not only extend the photo absorption of BiOCl from the UV to the visible light region but also greatly increase the generation and transfer rate of charge carriers because of its narrowed band gap and the localized surface plasmon resonance (LSPR) effect of metallic Ag. Under visible light irradiation, the Cr-BOC/Ag showed the remarked enhancement on PFC performance when the optimum contents of Cr doping and Ag loading was 14.4% and 4%, respectively. The trapping experiments and multiple characterizations demonstrated that the advantageous combination of Cr doping effect and SPR effect induced by the Ag nanoparticles is responsible for the high generation rate of oxidative species and effective charge carriers transfer. By using RhB as fuel, approximately 75.1% color removal efficiency and 8.38% Coulombic efficiency were obtained under visible light irradiation for 240 min, which are higher than that of MO and TC. And, the Jsc and Voc of Cr-BOC/Ag photoanode were measured to be 0.0073 mA/cm2 and 0.543 V.
关键词： photocatalytic degradation,SPR,BiOCl,coulombic efficiency,visible light,fuel cell
更新于2025-11-14 17:03:37
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Electrochemical surface plasmon resonance (EC-SPR) aptasensor for ampicillin detection
摘要： Surface plasmon resonance technique is highly sensitive to various processes taking place on a metal film and it has emerged as a powerful label-free method to study molecular binding processes taking place on a surface. Another important but less explored area of applications is the use of hybrid methods which combine electrochemistry with optical methods for better monitoring and understanding of biochemical processes. A detection method based on surface plasmon resonance was developed for ampicillin, applying electrochemical techniques for the elaboration and characterization of the aptasensing platform used in this study. Ampicillin is a broad-spectrum β-lactam antibiotic, used both in human and veterinary medicine for the treatment and prevention of primary respiratory, gastrointestinal, urogenital, and skin bacterial infections. It is widely used because of its broad spectrum and low cost. This widespread use can result in the presence of residues in the environment and in food leading to health problems for individuals who are hypersensitive to penicillins. The gold chip was functionalized through potential-assisted immobilization, using multipulse amperometry, first with a thiol-terminated aptamer, as a specific ligand and secondly, using the same procedure, with mercaptohexanol, used to cover the unoccupied binding sites on the gold surface in order to prevent the nonspecific adsorption of ampicillin molecules. After establishing the optimal conditions for the chip functionalization, different concentrations of ampicillin were detected in real time, in the range of 2.5–1000 μmol L?1, with a limit of detection of 1 μmol L?1, monitoring the surface plasmon resonance response. The selectivity of the aptasensor was proven in the presence of other antibiotics and drugs, and the method was successfully applied for the detection of ampicillin from river water.
关键词： Multipulse amperometry,Electrochemical surface plasmon resonance (EC-SPR),Ampicillin,QCM,Antibiotic detection,SPR aptasensor
更新于2025-09-23 15:23:52
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Light enhanced room temperature resistive NO2 sensor based on a gold-loaded organic–inorganic hybrid perovskite incorporating tin dioxide
摘要： A material is described for sensing NO2 in the gas phase. It has an architecture of type Au/MASnI3/SnO2 (where MA stands for methylammonium cation) and was fabricated by first synthesizing Au/MASnI3 and then crystallizing SnO2 on the surface by calcination. The physical and NO2 sensing properties of the composite were examined at room temperature without and with UV (365 nm) illumination, and the NO2-sensing mechanism was studied. The characterization demonstrated the formation of a p-n heterojunction structure between p-MASnI3 and n-SnO2. The sensor, best operated at a voltage of 1.1 V at room temperature, displays superior NO2 sensing performance. Figures of merit include (a) high response (Rg/Ra = 240 for 5 ppm NO2; where Rg stands for the resistance of a sensor in test gas, and Ra stands for the resistance of a sensor in air), (b) fast recovery (about 12 s), (c) excellent selectivity compared to sensors based on the use of SnO2 or Au/SnO2 only, both at room temperature under UV illumination; (d) a low detection limit (55 ppb), and (e) a linear response between 0.5 and 10 ppm of NO2. The enhanced sensing performance is mainly attributed to the high light absorption capacity of MASnI3, the easy generation and transfer of photo-induced electrons from MASnI3 to the conduction band of SnO2, and the catalytic effect of gold nanoparticles.
关键词： Light absorbing material,SPR effect,Photo generated electrons,Gas sensing,P-n junction,Catalytic effect,Heterojunction,SnO2,UV light,MASnI3
更新于2025-09-23 15:23:52
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An automatic multi-thread image segmentation embedded system for surface plasmon resonance sensor
摘要： In order to reduce the uncertainties associated with manual selection of regions of interest (ROIs) commonly used in Surface Plasmon Resonance (SPR) imaging system, we proposed and implemented an automatic image segmentation method in an embedded system to facilitate the potential real-time applications. Intuitive marker-controlled watershed algorithm is developed to segment ROIs (reaction, blank, and background regions) from images acquired from an experimental image SPR system. The marker assignment algorithms and pre-processing algorithms are executed in parallel by multi-threading programming on the multi-core embedded system to both real-time and good quality of segmentation. This method exhibited a good robustness in a series of ROIs segmentation test. Furthermore, the intensity response from triplicate detection of glucose standard solutions indicated a good reproducibility of data. The linear range was from 2.5 mg/mL to 20.4 mg/mL, with a correlation coefficient (R2) of 0.999 and sensitivity of 2.69 a.u./mg/mL. In conclusion, the proposed automatic image segmentation method effectively makes the measurement more precise and simplified.
关键词： Optical sensor,Surface plasmon resonance (SPR),Biosensor,Watershed algorithm,Image segmentation
更新于2025-09-23 15:23:52
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The Effect of Physical and Geometric Parameters on the Surface Plasmon Resonance Response of a Fiber Optic Biosensor: Sensitivity Analysis and Numerical Optimization
摘要： The study of the influence of optical and geometric parameters on the spectral response of the biosensor is an important step towards the optimization of these parameters. In this study, an improved SPR biosensor with a high resolution is proposed. The present SPR biosensor is based on an optical fiber that takes the place of the prism, compared with the conventional configuration, in order to simplify the detection process, overcome the stresses caused by the massive prism and obtain a reliable and efficient miniature device. The modeling procedure is based on a matrix formalism developed for the optical studies of multilayer media. We have discussed the effect of physical and optical parameters on the resonance curves, from the theoretical analysis of the transmitted power. The obtained results show that the response of the biosensor is highly dependent on these parameters. The optimum values of the length of the sensitive area, the core diameter of the optical fiber, the thickness of the metal layer and the refractive index of external environment have been determined.
关键词： Optical Fiber,Biosensors,Numerical Optimization,Surface Plasmon Resonance SPR,Sensitivity
更新于2025-09-23 15:23:52
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Reflective SPR Sensor for Simultaneous Measurement of Nitrate Concentration and Temperature
摘要： In this paper, a reflective fiber optic sensor based on surface plasmon resonance (SPR) was proposed to measure nitrate concentration and temperature simultaneously. The sensor adopted reflective structure, and used gold film as metal film for exciting SPR. Then, Cu-nanoparticles/carbon nanotubes composite film was used as sensitive material to measure nitrate concentration, and it was coated on the surface of the gold film by the dip coating method. Finally, polydimethylsiloxane was coated on part of the sensing probe to produce two independent resonance dips in the output spectrum. When the nitrate concentration and temperature changed, the two resonance dips would all move, but with different sensitivities. By monitoring the wavelength shifts of the two dips, the nitrate concentration and temperature could be measured simultaneously with using the dual-wavelength matrix method. Experimental results demonstrated that the measurement sensitivity of the nitrate concentration could reach 3.25 nm/lg[M], and the temperature measurement sensitivity was ?2.02 nm/°C. Moreover, the sensor had high-mechanical strength and was easy to package, which could be applied to remote measurement field.
关键词： reflective surface plasmon resonance (SPR),optical fiber sensor,Nitrate concentration,simultaneous measurement,temperature
更新于2025-09-23 15:22:29
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Sensitivity Enhancement of a Surface Plasmon Resonance with Tin Selenide (SnSe) Allotropes
摘要： Single layers of tin selenide (SnSe), which have a similar structure as graphene and phosphorene, also show excellent optoelectronic properties, and have received much attention as a two-dimensional (2D) material beyond other 2D material family members. Surface plasmon resonance (SPR) sensors based on three monolayer SnSe allotropes are investigated with the transfer matrix method. The simulated results have indicated that the proposed SnSe-containing biochemical sensors are suitable to detect different types of analytes. Compared with the conventional Ag-only film biochemical sensor whose sensitivity is 116°/RIU, the sensitivities of these SnSe-based biochemical sensors containing α-SnSe, δ-SnSe, ε-SnSe, were obviously increased to 178°/RIU, 156°/RIU and 154°/RIU, respectively. The diverse biosensor sensitivities achieved with these three SnSe allotropes suggest that these 2D materials can adjust SPR sensor properties.
关键词： SPR sensor,high sensitivity,SnSe allotrope
更新于2025-09-23 15:22:29
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One-step synthesis of hierarchical AuNPs/Cd0.5Zn0.5S nanoarchitectures and their application as an efficient photocatalyst for hydrogen production
摘要： The hierarchical AuNPs/Cd0.5Zn0.5S hybrids are directly fabricated via a facile one-step in-situ hydrothermal method. The as-prepared AuNPs/Cd0.5Zn0.5S hybrids demonstrate superior photocatalytic performance toward hydrogen production under visible light irradiation. The hydrogen evolution rate of the 5 wt% AuNPs/Cd0.5Zn0.5S synthesized with in-situ hydrothermal method can be 7.1 times greater than that of pure Cd0.5Zn0.5S and as much as 2.5 times of 5 wt% AuNPs loaded Cd0.5Zn0.5S synthesized with photodeposition method. Systematical investigations reveal that the enhanced photocatalytic performance of the one-step in-situ prepared AuNPs/Zn0.5Cd0.5S can be attributed to the inherent SPR effect and favorable electron transfer properties of AuNPs, as well as the rational hierarchical nanoarchitectures that allow AuNPs to be uniformly incorporated into Zn0.5Cd0.5S matrix. This one-step in-situ fabrication method provides a simple and efficient route to synthesize well-defined heterocatalysts.
关键词： AuNPs/Cd0.5Zn0.5S,Photocatalysis,Hydrogen evolution,SPR,One-step
更新于2025-09-23 15:22:29