Raman sensing of fuel gases using a reflective coating capillary optical fiber

Buric, Michael; Chen, K.; Falk, Joel; Velez, Raymond A.; Woodruff, Steven D.

doi:10.1117/12.818746

Cited by 12 publications

(10 citation statements)

References 6 publications

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“…We have previously shown that this configuration can be used to collect significantly more Raman light than a diffraction-limited, unconfined configuration. Figure 6 is a diagram of the Raman light collection system described previously [9,15].…”

Section: Enhanced Raman Scattering Collection Using Metal Waveguidesmentioning

confidence: 99%

“…Measurement of the Stokes wavelength and its intensity permits determination of the composition and density of the gaseous analyte flowing inside the capillary. This technique has been shown to be more effective than unconfined Raman collection [15], but the exact theoretical magnitude of collection improvement has been unknown because of the complicated multimode characteristics of metal-lined capillaries. In order to detail precisely the Raman optical power that can be collected using a metal-lined capillary waveguide, we must first know the loss coefficient of each mode that can propagate in the guide.…”

Section: Introductionmentioning

confidence: 99%

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Multimode metal-lined capillaries for Raman collection and sensing

et al. 2010

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Reflective metal-lined capillary waveguides are useful for laser-power delivery or for collecting scattered light in sensing applications. We theoretically examine the multimode propagation of polarized light in largediameter, metallized, capillary waveguides using a new perturbation technique valid for all waveguide modes. This modeling permits prediction of the collection efficiency of Raman or fluorescent light produced in the waveguide at all angles. These theoretical results are supported by measuring the intensity and angular distribution of collected scattered gas-Raman Stokes power.

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Section: Enhanced Raman Scattering Collection Using Metal Waveguidesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multimode metal-lined capillaries for Raman collection and sensing

et al. 2010

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“…The sensitivity of Raman spectroscopy covers a wide concentration range, down to very low concentration, 1,2 even to sub-ppm levels 3,4 . Raman spectroscopy has been widely used for gas analysis in various domains of investigation such as monitoring of polluted air 5 or automobile exhaust gases, 1 fuel gas analysis, [6][7][8] diagnosis and monitoring of disease states by human breath analysis, 3,4,9 controlling and monitoring of fruit ripening, 10 analyzing of gas bubbles appearing as defects inside industrial glasses to optimize production process. 11 Other applications can also be found in the field of environmental gas sensing, e.g.…”

mentioning

confidence: 99%

Quantitative Measurements of Composition, Pressure, and Density of Microvolumes of CO₂–N₂ Gas Mixtures by Raman Spectroscopy

Caumon

Tarantola

et al. 2019

Anal. Chem.

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Quantitative analysis of gases by Raman spectroscopy is based on relative Raman scattering cross-sections (RRSCS) and the evolution of different spectral parameters (peak position, peak area, peak intensity, etc.). However, most of the calibration data were established at low pressure (low density) and without evaluating the effect of the composition. Using these data may lead to considerable errors, especially when applied to gas mixtures at high pressure as found in natural fluid inclusions. The aim of this study is to reevaluate the RRSCS of CO2 and to establish new calibration data based on the variation of CO2 Fermi diad splitting as a function of pressure (density) and composition over a pressure range of 5 to 600 bars at 22 and 32 °C. A high-pressure optical cell system (HPOC) and a heating-cooling stage were used for Raman in-situ analyses at controlled PTX conditions. Our experimental results show that the RRSCS of CO2 varies slightly with pressure but can be considered constant over the studied pressure range. It can be used to measure the proportion of CO2 in gas mixtures with an uncertainty of about ± 0.5 mol%. Different polynomial equations were provided to calculate pressure and density of CO2-N2 gas mixtures with an uncertainty of ± 20 bar or 0.01 g.cm −3. A comparison of PVTX properties of natural CO2-N2 fluid inclusions hosted in quartz from the Central Alps (Switzerland) obtained by Raman measurement and as derived from phase transition temperatures by microthermometry experiments shows comparable values. ASSOCIATED CONTENT Supporting Information The Supporting Information is available free of charge on the ACS Publications website. Detailed uncertainty calculations and the coefficients of regression polynomial equations 3, 4 and 5 (PDF)

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“…Measurement of the Stokes wavelength and its intensity permits determination of the composition of the gaseous analytes flowing inside the capillary. This technique has been shown to be more effective than unconfined Raman collection [2], but the exact theoretical magnitude of collection improvement has been unknown because of the complicated multimode characteristics of metal-lined capillaries. In order to detail precisely the Raman optical power that can be collected using a metal-lined capillary waveguide, we must first know the loss coefficient of each mode that can propagate in the guide.…”

Section: Discussionmentioning

confidence: 99%

Optical efficiency in metal-lined capillary waveguide Raman sensors

et al. 2011

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Researchers have long sought to improve collection efficiencies in scattered-light sensing applications. Herein, we demonstrate efficient collection of Raman scattered light from gaseous samples. This enables the accurate, real-time, simultaneous measurement of otherwise difficult to distinguish molecular gasses or hydrocarbons. Hollow capillary waveguides, lined with a metal and dielectric over-coating, have often been used to deliver IR laser light to a target. We show that these waveguides can be used as both a sample holder for Raman gasses and as a laser-pumped optical cell which can collect Raman scattered light from these gasses. We extend existing low mode-order capillary waveguide analysis to treat higher order modes. This extension allows a robust computer simulation to accurately predict the spontaneous Raman scattering power that can be collected by the waveguide. We verify our new theoretical models with experimental measurements of Raman signals from a nitrogen filled waveguide. We demonstrate a cutback experiment which verifies our new theoretical predictions of the variation of scattering collection efficiency with guide dimensions. The prediction accuracy of our simulations allows us to design spectrometers and detectors to maximize Raman-light throughput in a high-sensitivity gas detection system.

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Raman sensing of fuel gases using a reflective coating capillary optical fiber

Cited by 12 publications

References 6 publications

Multimode metal-lined capillaries for Raman collection and sensing

Multimode metal-lined capillaries for Raman collection and sensing

Quantitative Measurements of Composition, Pressure, and Density of Microvolumes of CO₂–N₂ Gas Mixtures by Raman Spectroscopy

Optical efficiency in metal-lined capillary waveguide Raman sensors

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Raman sensing of fuel gases using a reflective coating capillary optical fiber

Cited by 12 publications

References 6 publications

Multimode metal-lined capillaries for Raman collection and sensing

Multimode metal-lined capillaries for Raman collection and sensing

Quantitative Measurements of Composition, Pressure, and Density of Microvolumes of CO2–N2 Gas Mixtures by Raman Spectroscopy

Optical efficiency in metal-lined capillary waveguide Raman sensors

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Product

Resources

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Quantitative Measurements of Composition, Pressure, and Density of Microvolumes of CO₂–N₂ Gas Mixtures by Raman Spectroscopy