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Stable Isotopic Analysis of Atmospheric Methane by Infrared Spectroscopy by Use of Diode Laser Difference-Frequency Generation

Published

Author(s)

M. E. Trudeau, Pin Chen, G de Andreade Garcia, Leo W. Hollberg, P P. Tans

Abstract

An infrared absorption spectrometer has been constructed to measure the stable isotopic composition of atmospheric methane samples. The spectrometer employs periodically poled lithium niobate (PPLN) to generate 15 W of tunable difference frequency radiation from two near infrared diode lasers that probes the 3 rotational-vibrational band of methane at 3.4 microns. To enhance the signal, methane is extracted from 25 L of air using a cryogenic chromatographic column and is expanded into the multipass cell for analysis. A measurement precision of 12 is demonstrated for both 13C and D.
Citation
Applied Optics
Volume
45 No 17

Keywords

air, difference frequency generation, infrared, isotopes, methane, periodically poled lithium niobate, spectroscopy

Citation

Trudeau, M. , Chen, P. , de Andreade Garcia, G. , Hollberg, L. and Tans, P. (2006), Stable Isotopic Analysis of Atmospheric Methane by Infrared Spectroscopy by Use of Diode Laser Difference-Frequency Generation, Applied Optics (Accessed March 1, 2024)
Created May 31, 2006, Updated October 12, 2021