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Start Over Topic fiber optics
5 results

1. Investigation of Distributed Moisture and Temperature Measurements in Transformers Using Fiber Optics Sensors.

Author

Ansari, Muhammad A., Martin, Daniel, and Saha, Tapan Kumar

Subjects
*MOISTURE measurement, *FIBER optics, *ELECTRIC transformers, *OPTICAL fiber detectors, *TEMPERATURE measurements, *DETECTORS
Abstract

The measurement of water inside a transformer is essential to maintain its reliable operation, as the water content can increase as the transformer ages. This measurement is frequently performed by a utility as a part of its periodic maintenance activities. In this paper, the application of optical fiber sensors as an online method to measure water content of paper inside an operating transformer is presented. There are several advantages of using these sensors, including their size, lightweight, flexibility, multiplexing, no-electromagnetic interference, etc. A unique benefit of fiber optic technology is that sensors can be embedded into the winding structure and operate in areas of high electric field strength. For this work, fiber optic water and temperature sensors are investigated by comparing their measurements to a commercial water activity probe immersed in oil. The study found that the determination of water content by fiber optic sensors compared closely with other techniques, which lead to the conclusion that they can be an effective technology for water measurement in an operational transformer. [ABSTRACT FROM AUTHOR]

Published
2019
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2. Characterization of a multicore fiber image guide for nonlinear endoscopic imaging using two-photon fluorescence and second-harmonic generation

Author

Anikitos, Garofalakis, Sergei G, Kruglik, Tigran, Mansuryan, André, Gillibert, Luc, Thiberville, Frédéric, Louradour, Christine, Vever-Bizet, Genevieve, Bourg-Heckly, Sorbonne Université (SU), Institut de Biologie Paris Seine (IBPS), Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Photonique Fibre et Sources Cohérentes (XLIM-PHOT), XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), Unité de biostatistiques [CHU Rouen], Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-CHU Rouen, Normandie Université (NU), Equipe Quantification en Imagerie Fonctionnelle (QuantIF-LITIS), Laboratoire d'Informatique, de Traitement de l'Information et des Systèmes (LITIS), Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Université Le Havre Normandie (ULH), and Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie)

Subjects
Paper, Photons, [SDV]Life Sciences [q-bio], Endoscopy, Signal Processing, Computer-Assisted, Equipment Design, nonlinear microscopy, fluorescence microscopy, Imaging, Microscopy, Fluorescence, Multiphoton, Image Processing, Computer-Assisted, endoscopic imaging, Humans, medical and biological imaging, Lung, Optical Fibers, fiber optics
Abstract

International audience; Multiphoton microscopy (MPM) has the capacity to record second-harmonic generation (SHG) and endogenous two-photon excitation fluorescence (2PEF) signals emitted from biological tissues. The development of fiber-based miniaturized endomicroscopes delivering pulses in the femtosecond range will allow the transfer of MPM to clinical endoscopy. We present real-time SHG and 2PEF ex vivo images using an endomicroscope, which totally complies with clinical endoscopy regulations. This system is based on the proximal scanning of a commercial multicore image guide (IG). For understanding the inhomogeneities of the recorded images, we quantitatively characterize the IG at the single-core level during nonlinear excitation. The obtained results suggest that these inhomogeneities originate from the variable core geometries that, therefore, exhibit variable nonlinear and dispersive properties. Finally, we propose a method based on modulation of dispersion precompensation to address the image inhomogeneity issue and, as a proof of concept, we demonstrate its capability to improve the nonlinear image quality.

Published
2019

3. Submillimeter diameter rotary-pullback fiber-optic endoscope for narrowband red-green-blue reflectance, optical coherence tomography, and autofluorescence in vivo imaging

Author

Reid Tingley, Anthony M. D. Lee, Max Manning, Calum MacAulay, Geoffrey Hohert, Pierre Lane, Elham Abouei, Dianne Miller, Ian Janzen, Andrea Louise Buenconsejo, and Jessica N. McAlpine

Subjects
Paper, Catheters, Materials science, Optical fiber, genetic structures, Biomedical Engineering, multimodal imaging, Signal-To-Noise Ratio, autofluorescence, 01 natural sciences, law.invention, 010309 optics, Biomaterials, Narrowband, Optics, Optical coherence tomography, law, 0103 physical sciences, Image Processing, Computer-Assisted, Endomicroscopy, medicine, Animals, Fiber Optic Technology, fiber optics, Endoscopes, optical coherence tomography, medicine.diagnostic_test, Special Section on Biomedical Imaging and Sensing, business.industry, Optical Imaging, Endoscopy, Epithelial Cells, endomicroscopy, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Autofluorescence, Signal-to-noise ratio (imaging), RGB color model, red-green-blue imaging, sense organs, business, Tomography, Optical Coherence, Preclinical imaging
Abstract

A fiber-based endoscopic imaging system combining narrowband red-green-blue (RGB) reflectance with optical coherence tomography (OCT) and autofluorescence imaging (AFI) has been developed. The system uses a submillimeter diameter rotary-pullback double-clad fiber imaging catheter for sample illumination and detection. The imaging capabilities of each modality are presented and demonstrated with images of a multicolored card, fingerprints, and tongue mucosa. Broadband imaging, which was done to compare with narrowband sources, revealed better contrast but worse color consistency compared with narrowband RGB reflectance. The measured resolution of the endoscopic system is 25 μm in both the rotary direction and the pullback direction. OCT can be performed simultaneously with either narrowband RGB reflectance imaging or AFI.

Published
2019

4. Fiber-optic plasmonic probe with nanogap-rich Au nanoislands for on-site surface-enhanced Raman spectroscopy using repeated solid-state dewetting

Author

Jae-Beom Kim, Jihyun Kwak, Wonkyoung Lee, Sang-In Bae, and Ki-Hun Jeong

Subjects
Paper, Optical fiber, Materials science, Biomedical Engineering, Spectrum Analysis, Raman, 01 natural sciences, plasmonics, law.invention, 010309 optics, Biomaterials, symbols.namesake, Folic Acid, Limit of Detection, law, 0103 physical sciences, Fiber Optic Technology, Nanotechnology, Dewetting, Thin film, Plasmon, fiber optics, Multi-mode optical fiber, business.industry, technology, industry, and agriculture, Signal Processing, Computer-Assisted, Equipment Design, Surface-enhanced Raman spectroscopy, surface-enhanced Raman spectroscopy, Atomic and Molecular Physics, and Optics, Nanostructures, Electronic, Optical and Magnetic Materials, Nanolithography, Sensing, symbols, nanofabrication, Optoelectronics, Gold, solid-state dewetting, Raman spectroscopy, business
Abstract

We report a fiber-optic plasmonic probe with nanogap-rich gold nanoislands for on-site surface-enhanced Raman spectroscopy (SERS). The plasmonic probe features nanogap-rich Au nanoislands on the top surface of a single multimode fiber. Au nanoislands were monolithically fabricated using repeated solid-state dewetting of thermally evaporated Au thin film. The plasmonic probe shows 7.8×106 in SERS enhancement factor and 100 nM in limit-of-detection for crystal violet under both the excitation of laser light and the collection of SERS signals through the optical fiber. The fiber-through measurement also demonstrates the label-free SERS detection of folic acid at micromolar level. The plasmonic probe can provide a tool for on-site and in vivo SERS applications.

Published
2019