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In this paper, we have conducted a comparative study between hetero-core optical fiber localized surface plasmon resonance-based pH sensors that have been coated with a combination of different pH-sensitive polymers using the self-assembling layer-by-layer technique in the acidic pH range of 4.0-6.0. We have found that the pH response of the sensors in the given pH range increased with an increase in the number of self-assembled bilayers, and have concluded that the Poly-L-Lysine, Poly Acrylic Acid pair containing 30 layers had the highest optical loss change of 0.315 dB in response to pH change in the range of 4.0-5.5 at 650 nm wavelength out of all the other combinations.
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http://dx.doi.org/10.1364/OE.559509 | DOI Listing |
In this paper, we have conducted a comparative study between hetero-core optical fiber localized surface plasmon resonance-based pH sensors that have been coated with a combination of different pH-sensitive polymers using the self-assembling layer-by-layer technique in the acidic pH range of 4.0-6.0.
View Article and Find Full Text PDFSensors (Basel)
November 2024
Department of Natural and Environmental Sciences, Faculty of Science, Academic Assembly, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan.
Techniques for monitoring calcium carbonate and silica deposits (scale) in geothermal power plants and hot spring facilities using fiber optic sensors have already been reported. These sensors continuously measure changes in light transmittance with a detector and, when applied to field tests, require the installation of a power supply and sensor monitoring equipment. However, on some sites, a power supply may not be available, or a specialist skilled in handling scale sensors is required.
View Article and Find Full Text PDFAnal Chim Acta
September 2024
National Engineering Research Center of Fiber Optic Sensing Technology and Networks, Wuhan University of Technology, Wuhan, 430070, China. Electronic address:
Background: Cobalt, an essential trace element, is vital for maintaining human nervous system function, aiding in DNA synthesis, and contributing to red blood cell production. It is helpful for disease diagnosis and treatment plan evaluation by precisely monitoring its concentration changes in the human body. Despite extensive efforts made, due to its ultra-low concentration, the current limit of detection (LOD) as reported is still inadequate and cannot be satisfied with the precise clinical applications.
View Article and Find Full Text PDFIn this paper, we describe the first demonstration of an optical fiber sensor based on two cascaded architectures of the Mach-Zehnder interferometer (MZI) with an up-down-tapered (UDT) hetero-core fiber structure for simultaneous pH measurement at two different spatial locations. The two fiber structures, namely structures I and II, were fabricated by sandwiching a 45 mm and 60 mm long piece of no-core fiber (NCF) between two single-mode fibers (SMFs), respectively. By inserting a down-taper between two adjacent up-tapers in the NCF section using the over-fusion splicing technique, the UDT hetero-core fiber structure was achieved.
View Article and Find Full Text PDFMaterials (Basel)
December 2023
Zhongshan Institute of Modern Industrial Technology of SCUT, South China University of Technology, Zhongshan 528400, China.
It is crucial to detect Pb accurately and rapidly. This work proposes an ultra-sensitive optical fiber surface plasmon resonance (SPR) sensor functionalized with glutathione (GSH) for label-free detection of the ultra-low Pb concentration, in which the refractive index (RI) sensitivity of the multimode-singlemode-multimode (MSM) hetero-core fiber is largely enhanced by the gold nanoparticles (AuNPs)/Au film coupling SPR effect. The GSH is modified on the fiber as the sensing probe to capture and identify Pb specifically.
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