Sensitive absorption spectroscopy using the quantum cascade lase,r
Edward A. WhittakerJames Floyd KellyRichard M. WilliamsSteven W. SharpeJohn S. HartmanCaire GmachlFederico CapassoDeborah L. SivcoJames N. BaillargeonAlfred Y. Cho
0
Citation
0
Reference
10
Related Paper
Abstract:
We have used frequency modulated quantum cascade lasers to make sensitive absorption spectroscopy detection of H20 and NO vapors at low pressure and low concentration. 5µ and 8µ lasers show excellent properties for sensitive spectroscopy.Keywords:
Quantum cascade laser
Based on the Off-axis Cavity Enhanced Absorption Spectroscopy(OA-CEAS)technique,a high sensitivity pollution gas detection system was made by using a tunable near infrared diode laser as light source and a high finesse optical cavity with two plan-concave mirrors of reflectivity of 97.97% as absorption cell.The absorption spectra of N2O gas mixtures centered at 6 561.39cm-1 were obtained. The relationship between the absorption intensity and gaseous concentration was obtained by recording the absorption spectra of N2O gas mixtures at different concentration.The line-width of absorption spectroscopy vs the gas pressure and the detection limit was discussed as well.The minimum detection concentration was found to be 86ppm using this cavity enhanced absorption spectroscopy system. Indicating the cavity enhanced absorption spectroscopy is a sensitive,easy manipulated,robust and simplified technique,which can be used for rapid gas analysis.
Cavity Ring-Down Spectroscopy
Finesse
Optical cavity
Cite
Citations (1)
This report is the 17th in a series on spectrochemical methods of analysis issued by IUPAC Commission V.4. It is concerned with the principles of laser absorption spectroscopy and its application in the optical wavelength region. The present report has four main sections: fundamentals of laser absorption spectroscopy, Doppler-limited spectroscopy, sub-Doppler laser spectroscopy, and time-resolved laser spectroscopy.
Molecular spectroscopy
Instrumental chemistry
Cite
Citations (0)
Cite
Citations (14)
Cavity Ring-Down Spectroscopy
Optical cavity
Cite
Citations (6)
Ultrasensitive optical spectroscopy technologies for environment monitoring, and in general, for gas analysis in the near Infrared are mainly based on the following spectroscopic methods: diode laser spectroscopy with multipass cells, with or without frequency modulation, photoacoustic spectroscopy, and since very recently, difference frequency spectroscopy with diode lasers. One of the most important issues of any monitoring technology, as important as the sensitivity, is its ability to provide absolute absorption coefficients without the need of complicated and cumbersome calibration procedures. Until now, two of the most sensitive optical spectroscopic technologies capable of providing this absolute information, Cavity Ringdown Spectroscopy and Intracavity Laser Absorption Spectroscopy have practically no use in this field. Due to recent advances, these two methods can now provide low-cost very compact field instruments working in the spectral range from 0.8 to 2.5 microns, with the smallest detectable absorption down to 10-10 (one over 10 billions) per one centimeter of the absorption path. This would result in the sub-ppb detection limit for moisture for example. Experimental results obtained with prototype field instruments developed by our group will be presented. Future perspectives will be discussed.
Photoacoustic Spectroscopy
Trace gas
Cite
Citations (3)
Tunable diode laser absorption spectroscopy has been applied in the fields of atmospheric chemistry and monitoring pollutant gases as a new method of measuring trace gases. The technique of remote sensing of CO and CO2 at 760 mm Hg pressure with tunable diode laser absorption spectroscopy in the near-infrared region is introduced. And the relationship between the second-harmonic spectrum of CO2 in Lorentzian line shape and the modulation amplitude is also presented.
Trace gas
Harmonic
Cite
Citations (3)
Continuous tunable, mid-infrared, quantum cascade lasers and Optical Parametric Oscillators combined with photoacoustic spectroscopy and cavity enhanced spectroscopy trace molecular gases, such as NO and HCN, at ppbv level for medical applications.
Quantum cascade laser
Photoacoustic Spectroscopy
Trace gas
Molecular spectroscopy
TRACE (psycholinguistics)
Cite
Citations (0)
Trace gas
Cite
Citations (0)
Tunable diode laser absorption spectroscopy (TDLAS) is a method to detect trace-gas qualitatively or quantitatively based on the tunable characteristic of the diode laser to obtain the absorption spectroscopy in the characteristic absorption region. The concentration of CO is measured by tunable diode laser absorption spectroscopy (TDLAS) technology in this paper. The experimental results of measurement signals are inversely processed by applying the overall second harmonic least squares data processing algorithm. The experimental results indicate that the signal strength of the second harmonic spectrum changes with CO concentration. But the widths of the 2f lineshapes have not changed. The components that influence the uncertainty of measurement results during measuring CO concentration by TDLAS are analyzed and the mathematic model is built. The standard uncertainty of components and evaluation of uncertainty of measurement results are given with the direct evaluation method in detail. The evaluation results indicate that the major factors affecting measurement uncertainty are the indicating value uncertainty of the apparatus, concentration definite value uncertainty of calibrating gas.
Harmonic
SIGNAL (programming language)
Cite
Citations (0)
Quantum cascade laser
Continuous wave
Cite
Citations (3)