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Kwaśny M, Bombalska A. Optical Methods of Methane Detection. SENSORS (BASEL, SWITZERLAND) 2023; 23:2834. [PMID: 36905038 PMCID: PMC10007260 DOI: 10.3390/s23052834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/02/2023] [Accepted: 03/02/2023] [Indexed: 06/18/2023]
Abstract
Methane is the most frequently analyzed gas with different concentrations ranging from single ppm or ppb to 100%. There are a wide range of applications for gas sensors including urban uses, industrial uses, rural measurements, and environment monitoring. The most important applications include the measurement of anthropogenic greenhouse gases in the atmosphere and methane leak detection. In this review, we discuss common optical methods used for detecting methane such as non-dispersive infrared (NIR) technology, direct tunable diode spectroscopy (TDLS), cavity ring-down spectroscopy (CRDS), cavity-enhanced absorption spectroscopy (CEAS), lidar techniques, and laser photoacoustic spectroscopy. We also present our own designs of laser methane analyzers for various applications (DIAL, TDLS, NIR).
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Cossel KC, Waxman EM, Finneran IA, Blake GA, Ye J, Newbury NR. Gas-phase broadband spectroscopy using active sources: progress, status, and applications. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. B, OPTICAL PHYSICS 2017; 34:104-129. [PMID: 28630530 PMCID: PMC5473295 DOI: 10.1364/josab.34.000104] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Broadband spectroscopy is an invaluable tool for measuring multiple gas-phase species simultaneously. In this work we review basic techniques, implementations, and current applications for broadband spectroscopy. We discuss components of broad-band spectroscopy including light sources, absorption cells, and detection methods and then discuss specific combinations of these components in commonly-used techniques. We finish this review by discussing potential future advances in techniques and applications of broad-band spectroscopy.
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Affiliation(s)
- Kevin C. Cossel
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Eleanor M. Waxman
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
| | - Ian A. Finneran
- Division of Chemistry & Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Geoffrey A. Blake
- Division of Chemistry & Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Jun Ye
- JILA, National Institute of Standards and Technology and University of Colorado, Department of Physics, University of Colorado, Boulder, CO 80309, USA
| | - Nathan R. Newbury
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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PCF-based cavity enhanced spectroscopic sensors for simultaneous multicomponent trace gas analysis. SENSORS 2011; 11:1620-40. [PMID: 22319372 PMCID: PMC3274003 DOI: 10.3390/s110201620] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 11/16/2010] [Accepted: 01/04/2011] [Indexed: 12/04/2022]
Abstract
A multiwavelength, multicomponent CRDS gas sensor operating on the basis of a compact photonic crystal fibre supercontinuum light source has been constructed. It features a simple design encompassing one radiation source, one cavity and one detection unit (a spectrograph with a fitted ICCD camera) that are common for all wavelengths. Multicomponent detection capability of the device is demonstrated by simultaneous measurements of the absorption spectra of molecular oxygen (spin-forbidden b-X branch) and water vapor (polyads 4v, 4v + δ) in ambient atmospheric air. Issues related to multimodal cavity excitation, as well as to obtaining the best signal-to-noise ratio are discussed together with methods for their practical resolution based on operating the cavity in a “quasi continuum” mode and setting long camera gate widths, respectively. A comprehensive review of multiwavelength CRDS techniques is also given.
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Schmidl G, Paa W, Triebel W, Schippel S, Heyer H. Spectrally resolved cavity ring down measurement of high reflectivity mirrors using a supercontinuum laser source. APPLIED OPTICS 2009; 48:6754-6759. [PMID: 20011015 DOI: 10.1364/ao.48.006754] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We investigate a cavity ring down setup that offers the possibility to measure the spectrally resolved reflectivities of high reflectivity mirrors. The setup consists of a resonator (ring down cavity) and an intensified CCD camera system combined with a spectrograph for spectral resolution. A commercial supercontinuum laser (350-1750 nm) is applied as a compact excitation source. It is based on a photonic crystal fiber that is pumped by a q-switched microchip laser (1.6 ns pulse duration, 25 kHz repetition rate). This combination allows simultaneously recording the transmittance of the cavity over a wide wavelength range determined by the excitation source and the spectral sensitivity of the detector. The photon lifetimes inside the cavity (ring down times) are measured with high spectral resolution by means of an intensified camera system. Subsequently shifting the "gate" of the image intensifier from short to long delay times after the excitation pulse allows calculation of the reflectivity spectrum of the mirrors. Comparison of these results with measurements using a conventional setup (laser diode 675 nm and photomultiplier tube) clearly shows the high potential of the method due to the multichannel excitation and the detection scheme.
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Affiliation(s)
- Gabriele Schmidl
- Institute of Photonic Technology, P.O. Box 100 239, 07702 Jena, Germany.
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Stelmaszczyk K, Rohwetter P, Fechner M, Queisser M, Czyzewski A, Stacewicz T, Wöste L. Cavity ring-down absorption spectrography based on filament-generated supercontinuum light. OPTICS EXPRESS 2009; 17:3673-3678. [PMID: 19259207 DOI: 10.1364/oe.17.003673] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We performed simultaneous, multispectral CRDS measurements that for the first time use the Supercontinuum light source. We called this approach Supercontinuum Cavity Ring-Down Spectrography (SC CRDSpectrography) and successfully applied it to measuring the absorption spectrum of NO2 gas at a concentration of 2 ppm. The extrapolated sensitivity of our setup was much greater, about 5 ppb. The ppb sensitivity level is comparable to this obtainable with single wavelength dye-lasers based CRDS systems. It is, therefore, feasible to construct extremely broadband and sensitive CRDS devices basing on the SC CRDSpectrography scheme.
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Affiliation(s)
- Kamil Stelmaszczyk
- Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany.
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Varma RM, Venables DS, Ruth AA, Heitmann U, Schlosser E, Dixneuf S. Long optical cavities for open-path monitoring of atmospheric trace gases and aerosol extinction. APPLIED OPTICS 2009; 48:B159-B171. [PMID: 19183574 DOI: 10.1364/ao.48.00b159] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
An incoherent broadband cavity-enhanced absorption spectroscopy setup employing a 20 m long optical cavity is described for sensitive in situ measurements of light extinction between 630 and 690 nm. The setup was installed at the SAPHIR atmospheric simulation chamber during an intercomparison of instruments for nitrate (NO(3)) radical detection. The long cavity was stable for the entire duration of the two week campaign. A detection limit of approximately 2 pptv for NO(3) in an acquisition time of 5 s was established during that time. In addition to monitoring NO(3), nitrogen dioxide (NO(2)) concentrations were simultaneously retrieved and compared against concurrent measurements by a chemiluminescence detector. Some results from the campaign are presented to demonstrate the performance of the instrument in an atmosphere containing water vapor and inorganic aerosol. The spectral analysis of NO(3) and NO(2), the concentration dependence of the water absorption cross sections, and the retrieval of aerosol extinction are discussed. The first deployment of the setup in the field is also briefly described.
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Affiliation(s)
- Ravi M Varma
- Department of Physics, University College Cork, Cork, Ireland
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Gong Y, Li B. Ray-transfer-matrix model for accurate pulsed cavity ring-down measurement in the mismatching case. APPLIED OPTICS 2008; 47:3860-3867. [PMID: 18641755 DOI: 10.1364/ao.47.003860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A theoretical model based on the ray-transfer matrix is developed for the pulsed cavity ring-down (CRD) technique to numerically investigate the influence of the geometric parameters of the pulsed-CRD arrangement on the CRD signal. By fitting the spatial distribution of the pulsed laser beam to that of the TEM(00) cavity mode, the geometric parameters are optimized to obtain perfect matching between the laser beam and the ring-down cavity. It is indicated by the numerical simulations that as long as the laser power exiting the ring-down cavity is fully collected, a single exponential-decay signal, identical to the perfectly-matched CRD signal, is obtained in the mismatching case to determine accurately the cavity decay time. Intensity fluctuations appear in the mismatched CRD signal if the laser power exiting the ring-down cavity is not fully collected. Both the conventional exponential decay fitting approach and a linear fitting procedure are employed to analyze these mismatched CRD signals and the latter is recommended to make an accurate pulsed-CRD measurement.
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Affiliation(s)
- Yuan Gong
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, Sichuan 610209, China.
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Fiedler SE, Hese A, Heitmann U. Influence of the cavity parameters on the output intensity in incoherent broadband cavity-enhanced absorption spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:073104. [PMID: 17672752 DOI: 10.1063/1.2752608] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The incoherent broadband cavity-enhanced absorption spectroscopy is a technique in measuring small absorptions over a broad wavelength range. The setup consists of a conventional absorption spectrometer using an incoherent lamp and a charge coupled device detector, as well as a linear optical cavity placed around the absorbing sample, which enhances the effective path length through the sample. In this work the consequences of cavity length, mirror curvature, reflectivity, different light injection geometries, and spot size of the light source on the output intensity are studied and the implications to the signal-to-noise ratio of the absorption measurement are discussed. The symmetric confocal resonator configuration is identified as a special case with optimum imaging characteristics but with higher requirements for mechanical stability. Larger spot sizes of the light source were found to be favorable in order to reduce the negative effects of aberrations on the intensity.
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Affiliation(s)
- Sven E Fiedler
- Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin, Germany.
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Fiedler SE, Hoheisel G, Ruth AA, Hese A. Incoherent broad-band cavity-enhanced absorption spectroscopy of azulene in a supersonic jet. Chem Phys Lett 2003. [DOI: 10.1016/j.cplett.2003.10.075] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Affiliation(s)
- Stephen M Ball
- University Chemical Laboratory, Cambridge University, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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Brown SS. Absorption Spectroscopy in High-Finesse Cavities for Atmospheric Studies. Chem Rev 2003; 103:5219-38. [PMID: 14664649 DOI: 10.1021/cr020645c] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Steven S Brown
- NOAA Aeronomy Lab, R/AL2, 325 Broadway, Boulder, CO 80305, USA
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Scherer JJ, Paul JB, Jiao H, O'Keefe A. Broadband ringdown spectral photography. APPLIED OPTICS 2001; 40:6725-6732. [PMID: 18364983 DOI: 10.1364/ao.40.006725] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A new technique that enables frequency-resolved cavity ringdown absorption spectra to be obtained over a large optical bandwidth by a single laser shot is described. The technique, ringdown spectral photography (RSP), simultaneously employs two key principles to record the time and frequency response of an optical cavity along orthogonal axes of a CCD array detector. Previously, the principles employed in RSP were demonstrated with narrow-band laser light that was scanned in frequency [Chem. Phys. Lett. 292, 143 (1998)]. Here, the RSP method is demonstrated using single pulses of broadband visible laser light. The ability to obtain broad as well as rotationally resolved spectra over a large bandwidth with high sensitivity is demonstrated.
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Affiliation(s)
- J J Scherer
- Los Gatos Research, 67 East Evelyn Avenue, Suite 3, Mountain View, California 94041, USA
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Ball SM, Povey IM, Norton EG, Jones RL. Broadband cavity ringdown spectroscopy of the NO3 radical. Chem Phys Lett 2001. [DOI: 10.1016/s0009-2614(01)00573-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Yoo YS, Kim JW, Lee JY, Hahn JW. High-resolution cavity ringdown spectroscopy with a Fabry–Perot etalon at the cavity output. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)01057-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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