A Raman cell based on hollow core photonic crystal fiber for human breath analysis

Chow, Kam Kong; Short, Michael; Lam, Stephen; McWilliams, Annette; Zeng, Haishan

doi:10.1118/1.4892381

Cited by 54 publications

(37 citation statements)

References 66 publications

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“…It should be noted that researchers use various technical solutions to provide the required levels of the Raman signals. Among them are the application of multipass and intracavity systems of excitation of Raman scattering, hollow‐core fibers, and surface enhancement . However, the most efficient and easiest approach used to increase the Raman signals is the compression of the gas being analyzed .…”

Section: Introductionmentioning

confidence: 99%

Pressure dependence of the Raman signal intensity in high‐pressure gases

Petrov

Matrosov

2016

J Raman Spectroscopy

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At present gas analysis based on Raman, spectroscopy is actively developed. In most cases, to achieve the required Raman signal intensity, compression of the gas medium is used. However, in comparison with normal conditions, the character of motion of molecules and their electric properties change in high‐pressure gas media, thereby violating a linear dependence of the Raman signal intensity on the concentration of molecules and the gas pressure. In the present work, a theoretical model is presented that describes the Raman signal intensity as a function of the pressure of the gas medium considering the compressibility factor, the internal field factor, and the instrumental factor. To verify the model, changes in the Raman signal intensities of vibrational bands of nitrogen and oxygen in the pressure range 1–80 atm and carbon dioxide in the pressure range 1–60 atm are investigated. Under these conditions, we observe a deviation of ~3% from a linear dependence for nitrogen, ~7% for oxygen and ~80% for carbon dioxide, which is in good agreement with the theoretical model. Raman shifts, half‐widths of Q‐branches of vibrational bands ν1 (and 2ν2 for carbon dioxide) of these molecules and also ratio of integral intensities I(2ν2)/I(ν1) for carbon dioxide under these conditions are investigated. Copyright © 2016 John Wiley & Sons, Ltd.

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Section: Introductionmentioning

confidence: 99%

Pressure dependence of the Raman signal intensity in high‐pressure gases

Petrov

Matrosov

2016

J Raman Spectroscopy

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“…A Raman‐breath analysis system based on long HCPCF in the NIR region has been developed and demonstrated a higher SNR and detection sensitivity over the previous prototype device, which was based on a capillary fibre. Similar results have been confirmed in the study by Eftekhari to obtain a controllable liquid suction and discharge.…”

Section: Major Categories Of Optical Fibres In Raman Spectroscopymentioning

confidence: 99%

Review of optical fibre probes for enhanced Raman sensing

Wang

Zeng

et al. 2017

J Raman Spectroscopy

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Raman scattering is a photon‐molecular interaction based on the kinetic modes of an analyte. It offers unique fingerprint‐type signals that allow molecular identification. A serious challenge frequently encountered in Raman measurements arises from the requirements of fast, real‐time remote sensing, fluorescence suppression, ultra‐micro concentration detection, small sample volumes and label‐free biological specimens. This review focuses on fibre‐optic probes for Raman spectroscopy, especially for enhanced sampling applications. It aims at providing an overview over contemporary technology and recent excellent researches, and helps identifying future developments necessary to bring the emerging technology to instrument manufacturers and end users. After a short introduction to surface‐enhanced Raman scattering technology, professional algorithms for design optimization of the fibre Raman probe will be discussed and general design considerations presented. Subsequently, various common geometries employed for enhanced Raman sampling are enumerated based on the types of waveguide fibres: multi‐fibre optodes, long‐pathlength capillary, microstructured photonic crystal fibre and other waveguide arrangements. Additionally, the relevant detection parameters are reviewed, such as target analyte, limit of detection, waveguide media and detection principle. The review also includes a brief summary of the advantages and limitations of various fibre Raman probes. Finally, the future work is discussed which will promote the reliability and the applicability of fibre enhanced Raman sensors. Copyright © 2017 John Wiley & Sons, Ltd.

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“…Another issue with both the HOF and the hollow core PCF probes is that the air trapped inside the hollow core can generate background Raman signals. The oxygen and carbon dioxide Raman peaks in hollow core fiber are quite strong when compared to tissue Raman signals .…”

Section: Instrumentationmentioning

confidence: 99%

Real‐time in vivo cancer diagnosis using raman spectroscopy

Wang

Zhao

Short

et al. 2014

Journal of Biophotonics

Self Cite

118

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Raman spectroscopy has becoming a practical tool for rapid in vivo tissue diagnosis. This paper provides an overview on the latest development of real-time in vivo Raman systems for cancer detection. Instrumentation, data handling, as well as oncology applications of Raman techniques were covered. Optic fiber probes designs for Raman spectroscopy were discussed. Spectral data pre-processing, feature extraction, and classification between normal/benign and malignant tissues were surveyed. Applications of Raman techniques for clinical diagnosis for different types of cancers, including skin cancer, lung cancer, stomach cancer, oesophageal cancer, colorectal cancer, cervical cancer, and breast cancer, were summarized. Schematic of a real-time Raman spectrometer for skin cancer detection. Without correction, the image captured on CCD camera for a straight entrance slit has a curvature. By arranging the optic fiber array in reverse orientation, the curvature could be effectively corrected.

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A Raman cell based on hollow core photonic crystal fiber for human breath analysis

Cited by 54 publications

References 66 publications

Pressure dependence of the Raman signal intensity in high‐pressure gases

Pressure dependence of the Raman signal intensity in high‐pressure gases

Review of optical fibre probes for enhanced Raman sensing

Real‐time in vivo cancer diagnosis using raman spectroscopy

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