Performance of Fiber-Optic Raman Probes for Analysis of Gas Mixtures in Enclosures

2002 ◽  
Vol 56 (1) ◽  
pp. 83-90 ◽  
Author(s):  
John M. Berg ◽  
Karen C. Rau ◽  
D. Kirk Veirs ◽  
Laura A. Worl ◽  
James T. McFarlan ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Fiber Optic ◽  
Detection Threshold ◽  
Gas Mixtures ◽  
Cylindrical Sample ◽  
Colored Glass ◽  
Signal Acquisition ◽  
Fiber Optic Probe ◽  
Detection Thresholds ◽  
Factors Affecting

The feasibility of using fiber-optic Raman probes to identify and quantify gases in enclosures is investigated by measuring and comparing detection thresholds using several probe and enclosure designs. Unfiltered, non-imaging, fiber-optic probes are shown to achieve lower detection thresholds than a filtered, imaging, fiberoptic probe, provided that light scattering within the sample enclosure is minimized and provided that a window is not used between the probe and the analyte gas. Achievable thresholds for hydrogen, oxygen, nitrogen, carbon monoxide, and methane in gas mixtures are demonstrated to be below 1 kPa with ten seconds signal acquisition and 0.1 kPa with twenty minutes signal acquisition with the use of 0.4 W of 532-nm excitation. Ambient carbon dioxide in air (.03 kPa) is shown to be detectable in a twenty minute acquisition, and ambient water vapor is well above the detection threshold. Background signals generated within the optical fibers remain the principal factors limiting detection thresholds. Factors affecting the magnitudes of these signals reaching the detector are investigated and discussed. A flat piece of light-absorbing colored glass tilted to direct reflected light away from the fiber-optic probe performs well as a beam stop to reduce background signal in a simple, cylindrical sample enclosure.

Novel Probe for Laser-Induced Breakdown Spectroscopy and Raman Measurements Using an Imaging Optical Fiber

1998 ◽  
Vol 52 (9) ◽  
pp. 1148-1153 ◽  
Author(s):  
Brian J. Marquardt ◽  
Dimitra N. Stratis ◽  
David A. Cremers ◽  
S. Michael Angel
Keyword(s):  
Raman Spectra ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Laser Induced Breakdown Spectroscopy ◽  
Fiber Optic Probe ◽  
Granite Sample ◽  
Soil Substrate ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown ◽  
Optic Probe

A fiber-optic probe designed for remote laser-induced breakdown spectroscopy (LIBS), Raman spectroscopy, and Raman imaging has been developed for the microanalysis of solid samples. The probe incorporates both single-strand optical fibers and an image guide and allows atomic emission and Raman analysis of any spot on a solid sample within a 5 mm diameter field of view. The real-time sample imaging aspects of the probe are demonstrated by measuring LIBS spectra from different regions of a granite sample and by measuring the Raman spectra of individual TiO2 and Sr(NO3)2 particles on a soil substrate. The ability to obtain remote Raman images of the TiO2 and Sr(NO3)2 particles on the soil substrate is also demonstrated. In this paper we discuss the design and implementation of the fiber-optic probe for obtaining LIBS spectra, Raman spectra, and Raman images.

Intensified Charge Coupled Device-Based Fiber-Optic Monitor for Rapid Remote Surface-Enhanced Raman Scattering Sensing

1992 ◽  
Vol 46 (11) ◽  
pp. 1608-1612 ◽  
Author(s):  
J. P. Alarie ◽  
D. L. Stokes ◽  
W. S. Sutherland ◽  
A. C. Edwards ◽  
T. Vo-Dinh
Keyword(s):  
Optical Fibers ◽  
Fiber Optic ◽  
Probe Design ◽  
Raman Signal ◽  
Fiber Optic Probe ◽  
Charge Coupled Device ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Intensified Charge Coupled Device ◽  
Optic Probe

This paper describes the development of an intensified charge coupled device (ICCD)-based fiber-optic monitor for remote Raman and surface-enhanced Raman (SERS) sensing. Both Raman and SERS data were obtained with the use of a fiber-optic probe design incorporating 20-m optical fibers carrying the Raman signal. Spectra were obtained in 5 milliseconds for Raman and 9 ms for SERS. The proposed system could be used for a highly sensitive portable Raman system for rapid and remote chemical sensing.

Synthesis, performance and growth mechanism of silver nanoparticle coated SERS fiber probe

2019 ◽  
Vol 107 (3) ◽  
pp. 305
Author(s):  
Mengmei Geng ◽  
Yuting Long ◽  
Tongqing Liu ◽  
Zijuan Du ◽  
Hong Li ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Absorption Spectrum ◽  
Reaction Time ◽  
Growth Mechanism ◽  
Fiber Optic ◽  
Fiber Optic Probe ◽  
Visible Absorption ◽  
Fiber Probe ◽  
Surface Enhanced Raman ◽  
Optic Probe

Surface-enhanced Raman Scattering (SERS) fiber probe provides abundant interaction area between light and materials, permits detection within limited space and is especially useful for remote or in situ detection. A silver decorated SERS fiber optic probe was prepared by hydrothermal method. This method manages to accomplish the growth of silver nanoparticles and its adherence on fiber optic tip within one step, simplifying the synthetic procedure. The effects of reaction time on phase composition, surface plasmon resonance property and morphology were investigated by X-ray diffraction analysis (XRD), ultraviolet-visible absorption spectrum (UV-VIS absorption spectrum) and scanning electron microscope (SEM). The results showed that when reaction time is prolonged from 4–8 hours at 180 °C, crystals size and size distribution of silver nanoparticles increase. Furthermore, the morphology, crystal size and distribution density of silver nanoparticles evolve along with reaction time. A growth mechanism based on two factors, equilibrium between nucleation and growth, and the existence of PVP, is hypothesized. The SERS fiber probe can detect rhodamin 6G (R6G) at the concentration of 10−6 M. This SERS fiber probe exhibits promising potential in organic dye and pesticide residue detection.

High-voltage monitoring by the fiber-optic recirculating measuring system

2020 ◽  
pp. 38-44
Author(s):  
A. V. Polyakov ◽  
M. A. Ksenofontov
Keyword(s):  
Optical Fibers ◽  
High Voltage ◽  
Optical Sensors ◽  
Electromagnetic Interference ◽  
Fiber Optic ◽  
Electric Power Industry ◽  
Measuring System ◽  
Voltage Range ◽  
External Electromagnetic Fields ◽  
Optic Communication

Optical technologies for measuring electrical quantities attract great attention due to their unique properties and significant advantages over other technologies used in high-voltage electric power industry: the use of optical fibers ensures high stability of measuring equipment to electromagnetic interference and galvanic isolation of high-voltage sensors; external electromagnetic fields do not influence the data transmitted from optical sensors via fiber-optic communication lines; problems associated with ground loops are eliminated, there are no side electromagnetic radiation and crosstalk between the channels. The structure and operation principle of a quasi-distributed fiber-optic high-voltage monitoring system is presented. The sensitive element is a combination of a piezo-ceramic tube with an optical fiber wound around it. The device uses reverse transverse piezoelectric effect. The measurement principle is based on recording the change in the recirculation frequency under the applied voltage influence. When the measuring sections are arranged in ascending order of the measured effective voltages relative to the receiving-transmitting unit, a relative resolution of 0,3–0,45 % is achieved for the PZT-5H and 0,8–1,2 % for the PZT-4 in the voltage range 20–150 kV.

FACTORS AFFECTING THE FLAMEPROOF MOTOR ENCLOSURES DESIGN FOR EXPLOITATION IN EXPLOSIVE GAS MIXTURES

2012 ◽  
Vol 11 (7) ◽  
pp. 1311-1316 ◽  
Author(s):  
Mihai Magyari ◽  
Sorin Burian ◽  
Martin Friedmann ◽  
Lucian Moldovan
Keyword(s):  
Gas Mixtures ◽  
Factors Affecting

scholarly journals Sensing, Actuation, and Control of the SmartX Prototype Morphing Wing in the Wind Tunnel

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 107
Author(s):  
Nakash Nazeer ◽  
Xuerui Wang ◽  
Roger M. Groves
Keyword(s):  
Wind Tunnel ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Experimental Testing ◽  
Single Mode ◽  
Fiber Optic Sensor ◽  
Sensor Data ◽  
Random Errors ◽  
Morphing Wing ◽  
Actuator Dynamics

This paper presents a study on trailing edge deflection estimation for the SmartX camber morphing wing demonstrator. This demonstrator integrates the technologies of smart sensing, smart actuation and smart controls using a six module distributed morphing concept. The morphing sequence is brought about by two actuators present at both ends of each of the morphing modules. The deflection estimation is carried out by interrogating optical fibers that are bonded on to the wing’s inner surface. A novel application is demonstrated using this method that utilizes the least amount of sensors for load monitoring purposes. The fiber optic sensor data is used to measure the deflections of the modules in the wind tunnel using a multi-modal fiber optic sensing approach and is compared to the deflections estimated by the actuators. Each module is probed by single-mode optical fibers that contain just four grating sensors and consider both bending and torsional deformations. The fiber optic method in this work combines the principles of hybrid interferometry and FBG spectral sensing. The analysis involves an initial calibration procedure outside the wind tunnel followed by experimental testing in the wind tunnel. This method is shown to experimentally achieve an accuracy of 2.8 mm deflection with an error of 9%. The error sources, including actuator dynamics, random errors, and nonlinear mechanical backlash, are identified and discussed.

scholarly journals Novel Bloch wave excitation platform based on few-layer photonic crystal deposited on D-shaped optical fiber

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Esteban Gonzalez-Valencia ◽  
Ignacio Del Villar ◽  
Pedro Torres
Keyword(s):  
Optical Fibers ◽  
High Performance ◽  
Light Propagation ◽  
Fiber Optic ◽  
Layer Structure ◽  
Optical Network ◽  
Building Blocks ◽  
Bloch Wave ◽  
Nanophotonic Devices ◽  
Wide Range

AbstractWith the goal of ultimate control over the light propagation, photonic crystals currently represent the primary building blocks for novel nanophotonic devices. Bloch surface waves (BSWs) in periodic dielectric multilayer structures with a surface defect is a well-known phenomenon, which implies new opportunities for controlling the light propagation and has many applications in the physical and biological science. However, most of the reported structures based on BSWs require depositing a large number of alternating layers or exploiting a large refractive index (RI) contrast between the materials constituting the multilayer structure, thereby increasing the complexity and costs of manufacturing. The combination of fiber–optic-based platforms with nanotechnology is opening the opportunity for the development of high-performance photonic devices that enhance the light-matter interaction in a strong way compared to other optical platforms. Here, we report a BSW-supporting platform that uses geometrically modified commercial optical fibers such as D-shaped optical fibers, where a few-layer structure is deposited on its flat surface using metal oxides with a moderate difference in RI. In this novel fiber optic platform, BSWs are excited through the evanescent field of the core-guided fundamental mode, which indicates that the structure proposed here can be used as a sensing probe, along with other intrinsic properties of fiber optic sensors, as lightness, multiplexing capacity and easiness of integration in an optical network. As a demonstration, fiber optic BSW excitation is shown to be suitable for measuring RI variations. The designed structure is easy to manufacture and could be adapted to a wide range of applications in the fields of telecommunications, environment, health, and material characterization.

Evaluation of Dry-Wet Transition in PEFC Under Load Changes Based on Laser Spectroscopy Using Fiber-Optic Probe

2019 ◽  
Vol 92 (8) ◽  
pp. 119-124
Author(s):  
Kosuke Nishida ◽  
Ryoga Nakauchi ◽  
Yuma Tabata ◽  
Toyofumi Umekawa ◽  
Masahiro Kawasaki
Keyword(s):  
Laser Spectroscopy ◽  
Fiber Optic ◽  
Fiber Optic Probe ◽  
Optic Probe

scholarly journals Longitudinal Raman Spectroscopic Observation of Skin Biochemical Changes due to Chemotherapeutic Treatment for Breast Cancer in Small Animal Model

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Myeongsu Seong ◽  
NoSoung Myoung ◽  
Songhyun Lee ◽  
Hyeryun Jeong ◽  
Sang-Youp Yim ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Animal Model ◽  
Raman Spectra ◽  
Fiber Optic ◽  
Animal Experiments ◽  
Small Animal ◽  
Fiber Optic Probe ◽  
Small Animal Model ◽  
Biochemical Compositions ◽  
Optic Probe

The cancer field effect (CFE) has been highlighted as one of indirect indications for tissue variations that are insensitive to conventional diagnostic techniques. In this research, we had a hypothesis that chemotherapy for breast cancer would affect skin biochemical compositions that would be reflected by Raman spectral changes. We used a fiber-optic probe-based Raman spectroscopy to perform preliminary animal experiments to validate the hypothesis. Firstly, we verified the probing depth of the fiber-optic probe (~800 μm) using a simple intravenous fat emulsion-filled phantom having a silicon wafer at the bottom inside a cuvette. Then, we obtained Raman spectra during breast cancer treatment by chemotherapy from a small animal model in longitudinal manner. Our results showed that the treatment causes variations of biochemical compositions in the skin. For further validation, the Raman spectra will have to be collected from more populations and spectra will need to be compared with immunohistochemistry of the breast tissue.

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