A closed-loop servo control based on balancing the gain of two probing frequencies is proposed for real-time Brillouin optical time-domain analysis (BOTDA) without post-processing. With the most basic BOTDA hardware setup, the system can perform measurement in 150 ms and track a sudden Brillouin frequency shift (BFS) change in excess of 300 MHz (corresponding to a temperature change of more than 250°C) over ∼5 km of fiber with a spatial resolution of 2 m. Moreover, the feedback loop is independent of the loss experienced by the probe and pump, with no requirement on the BFS uniformity along the fiber. All these advantages make the proposed system suitable for field applications in harsh environments.
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http://dx.doi.org/10.1364/OL.467617 | DOI Listing |
Sensors (Basel)
December 2024
Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou 510630, China.
Real-time online monitoring of track deformation during railway construction is crucial for ensuring the safe operation of trains. However, existing monitoring technologies struggle to effectively monitor both static and dynamic events, often resulting in high false alarm rates. This paper presents a monitoring technology for track deformation during railway construction based on dynamic Brillouin optical time-domain reflectometry (Dy-BOTDR), which effectively meets requirements in the monitoring of both static and dynamic events of track deformation.
View Article and Find Full Text PDFBiomed Opt Express
November 2024
Department of Physics, School of Sciences and Humanities, Nazarbayev University, 010000 Astana, Kazakhstan.
In this work, Brillouin light-scattering spectroscopy and optical backscattering reflectometry (OBR) using Mg-silica-NP-doped distributed sensing fibers were employed for monitoring local GHz visco-elastic properties and surface temperature, respectively, laser driven heating and ablation of chicken tissues. The spatial temperature distribution measured by OBR at various infrared laser heating powers and times was used to validate spatio-temporal local temperature variations modeled by the finite element method via solving Pennes' bioheat conduction equation. The reduction of viscosity and stiffness in chicken skin during its laser heating was attributed to water loss, protein denaturation and change in lipid phase behavior.
View Article and Find Full Text PDFSensors (Basel)
October 2024
State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, China.
J Colloid Interface Sci
January 2025
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Gothenburg, Sweden. Electronic address:
Hypothesis: Acoustic levitation is a suitable approach for studying processes occurring at the gas-liquid interfaces, as it allows its investigation in a contact-free manner while providing control over the gas phase. Here, we hypothesize that phase transitions induced by a CO rich atmosphere can be examined, at different length scales, in a contact-free manner.
Experimental: A system consisting of 12-hydroxysteric acid (HSA) soaps mixed with different ratios of monoethanolamine (MEA) and choline hydroxide, was prepared.
Biosensors (Basel)
July 2024
Department of Physics, School of Sciences and Humanities, Nazarbayev University, Astana 010000, Kazakhstan.
Noninvasive in situ monitoring of viscoelastic characteristics of corneal tissue at elevated temperatures is pivotal for mechanical property-informed refractive surgery techniques, including thermokeratoplasty and photorefractive keratectomy, requiring precise thermal modifications of the corneal structure during these surgical procedures. This study harnesses Brillouin light scattering spectroscopy as a biosensing platform to noninvasively probe the viscoelastic properties of ovine corneas across a temperature range of 25-64 °C. By submerging the tissue samples in silicone oil, consistent hydration and immiscibility are maintained, allowing for their accurate sensing of temperature-dependent mechanical behaviors.
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