Journal ArticleDOI
Extension of wavelength-modulation spectroscopy to large modulation depth for diode laser absorption measurements in high-pressure gases
TLDR
The effects of the nonideal performance parameters of commercial diode lasers are especially important away from the line center of discrete spectra, and these contributions become more pronounced for 2f signals with the large modulation depths needed for WMS at elevated pressures.Abstract:
Tunable diode laser absorption measurements at high pressures by use of wavelength-modulation spectroscopy (WMS) require large modulation depths for optimum detection of molecular absorption spectra blended by collisional broadening or dense spacing of the rovibrational transitions. Diode lasers have a large and nonlinear intensity modulation when the wavelength is modulated over a large range by injection-current tuning. In addition to this intensity modulation, other laser performance parameters are measured, including the phase shift between the frequency modulation and the intensity modulation. Following published theory, these parameters are incorporated into an improved model of the WMS signal. The influence of these nonideal laser effects is investigated by means of wavelength-scanned WMS measurements as a function of bath gas pressure on rovibrational transitions of water vapor near 1388 nm. Lock-in detection of the magnitude of the 2f signal is performed to remove the dependence on detection phase. We find good agreement between measurements and the improved model developed for the 2f component of the WMS signal. The effects of the nonideal performance parameters of commercial diode lasers are especially important away from the line center of discrete spectra, and these contributions become more pronounced for 2f signals with the large modulation depths needed for WMS at elevated pressures.read more
Citations
More filters
Journal ArticleDOI
Calibration-free wavelength-modulation spectroscopy for measurements of gas temperature and concentration in harsh environments
TL;DR: In this paper, a calibration-free wavelength-modulation spectroscopy with second harmonic detection (WMS-2f) for measurements of gas temperature and concentration in harsh environments is presented.
Journal ArticleDOI
Infrared laser-absorption sensing for combustion gases
TL;DR: A review of the development, application, and current capabilities of infrared laser-absorption spectroscopy (IR-LAS) sensors for combustion gases can be found in this paper.
Wavelength-modulation spectroscopy for measurements of gas temperature and concentration in harsh environments
TL;DR: Comparisons show the ability of the LOS calibration-free technique to gain useful information about multidimensional CFD models regarding temperature and H(2)O using a simple method that accounts for the influence of line-of-sight (LOS) nonuniformity on the absorption measurements.
Journal ArticleDOI
Applications of quantitative laser sensors to kinetics, propulsion and practical energy systems
TL;DR: In this article, the authors highlight three areas where quantitative sensing based on laser absorption has had strong influence: chemical kinetics, propulsion, and practical energy systems, and provide an overview of the current power and future potential of these modern diagnostic tools.
Journal ArticleDOI
Tunable diode laser absorption spectroscopy (tdlas) in the process industries – a review
TL;DR: TOLAS has become an accepted technique in the process industries for difficult measurement tasks, because it is compatible with high temperatures, pressures, dust levels and corrosive media as discussed by the authors. And TOLAS is used widely for continuous emission monitoring and process control with over 1,000 field instruments worldwide.
References
More filters
Journal ArticleDOI
The HITRAN molecular spectroscopic database: edition of 2000 including updates through 2001
Laurence S. Rothman,A. Barbe,D. Chris Benner,Linda R. Brown,Claude Camy-Peyret,Michel Carleer,Kelly Chance,Cathy Clerbaux,Cathy Clerbaux,V. Dana,V. M. Devi,André Fayt,Jean-Marie Flaud,Robert R. Gamache,Aaron Goldman,D. Jacquemart,Kenneth W. Jucks,Walter J. Lafferty,J.-Y. Mandin,Steven T. Massie,V. Nemtchinov,D.A. Newnham,Agnes Perrin,Curtis P. Rinsland,J. Schroeder,K.M. Smith,Mary Ann H. Smith,K. Tang,Robert A. Toth,J. Vander Auwera,Prasad Varanasi,Kouichi Yoshino +31 more
TL;DR: The HITRAN compilation consists of several components useful for radiative transfer calculation codes: high-resolution spectroscopic parameters of molecules in the gas phase, absorption cross-sections for molecules with very dense spectral features, aerosol refractive indices, ultraviolet line-by-line parameters and absorptionCross-sections, and associated database management software.
Journal ArticleDOI
Second-harmonic detection with tunable diode lasers — Comparison of experiment and theory
John Reid,Daniel Labrie +1 more
TL;DR: In this paper, a series of experiments are carried out by current modulating a tunable diode laser, and slowly ramping the wavelength to scan weak absorption lines in gases at pressures ranging from 2 to 60 Torr.
Journal ArticleDOI
Diode laser absorption sensors for gas-dynamic and combustion flows.
TL;DR: Recent advances in room-temperature, near-IR and visible diode laser sources for tele-communication, high-speed computer networks, and optical data storage applications are enabling a new generation of gas-dynamic and combustion-flow sensors based on laser absorption spectroscopy, suggesting likely directions for future research and development.
Journal ArticleDOI
Frequency modulation and wavelength modulation spectroscopies:comparison of experimental methods using a lead-salt diode laser
TL;DR: Both of the FMS methods, which require modulating the laser at frequencies >/= 150 MHz, give relatively poor results due to inefficient coupling of the modulation waveform to the laser current, and the re ults obtained agree well with theory.
Journal ArticleDOI
Laser diode wavelength-modulation spectroscopy for simultaneous measurement of temperature, pressure, and velocity in shock-heated oxygen flows
L. C. Philippe,Ronald K. Hanson +1 more
TL;DR: Wavelength modulation at 10 MHz of an AlGaAs laser diode, superposed on repetitive linear scans of wavelength, is applied to measure second-harmonic absorption line shapes of oxygen in the A band, and theoretical expressions of the harmonic line shapes are presented.
Related Papers (5)
Calibration-free wavelength-modulation spectroscopy for measurements of gas temperature and concentration in harsh environments
The HITRAN 2008 molecular spectroscopic database
Laurence S. Rothman,Iouli E. Gordon,Yurii L. Babikov,A. Barbe,D. Chris Benner,Peter F. Bernath,Manfred Birk,Luca Bizzocchi,Vincent Boudon,Linda R. Brown,Alain Campargue,Kelly Chance,Edward A. Cohen,L. H. Coudert,V. M. Devi,Brian J. Drouin,André Fayt,Jean-Marie Flaud,Robert R. Gamache,Jeremy J. Harrison,Jean-Michel Hartmann,Christian Hill,Joseph T. Hodges,D. Jacquemart,Antoine Jolly,Julien Lamouroux,R. J. Le Roy,Gang Li,David A. Long,O.M. Lyulin,C.J. Mackie,Steven T. Massie,Semen Mikhailenko,Holger S. P. Müller,Olga V. Naumenko,Andrei Nikitin,Johannes Orphal,V.I. Perevalov,Agnes Perrin,E. R. Polovtseva,Charlotte Richard,Mary Ann H. Smith,Evgeniya Starikova,Keeyoon Sung,S.A. Tashkun,Jonathan Tennyson,Geoff Toon,Vl.G. Tyuterev,G. Wagner +48 more
Second-harmonic detection with tunable diode lasers — Comparison of experiment and theory
John Reid,Daniel Labrie +1 more