Measurement of VOCs using open-path mid-infrared dual-comb spectroscopy

Cossel, Kevin C.

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https://hdl.handle.net/2142/104362 Copy

Description

Title

Measurement of VOCs using open-path mid-infrared dual-comb spectroscopy

Author(s)

Cossel, Kevin C.

Contributor(s)

• Newbury, Nathan R.
• Coddington, Ian
• Waxman, Eleanor
• Herman, Daniel I.
• Friedlein, Jacob T.
• Baumann, Esther
• Giorgetta, Fabrizio
• Ycas, Gabriel

Issue Date

2019-06-21

Keyword(s)

Atmospheric science

Abstract

Dual frequency comb spectroscopy (DCS) is a rapidly evolving technique that provides a high-resolution, broadband spectrometer with no instrument lineshape and near perfect frequency calibration\footnote{Coddington I, Newbury N, Swann W. Dual-comb spectroscopy. Optica. 2016 Apr 20;3(4):414. }. These features make DCS well suited for accurate measurements of multiple species simultaneously. Because the frequency comb lasers can be well collimated, such a system can be used for long open-path measurements with path lengths ranging from hundreds of meters to several kilometers. Open-path measurements of atmospheric gas species over these path lengths are well suited to quantify emissions from sources like oil and gas, forest fires, and industry. Previous demonstrations of open-path DCS have primarily been in the 1-2 $\mu$m spectral region; however, in order to reach the sensitivity necessary to detect many atmospheric trace constituents, including volatile organic compounds, operation in the mid-infrared is required. Here, we show a mid-infrared open-path dual comb spectrometer operating in the 3-5 $\mu$m spectral region. We have used this spectrometer to measure methane, ethane, propane, and butane isomers (arising primarily from oil and gas activity) across a 1-km-long path in Boulder, CO for 1 week with an ethane sensitivity of $\sim$0.1 ppb for a 2-minute time resolution. In addition, we show quantitative measurements of intentionally released acetone and isopropanol with a 1-$\sigma$ sensitivity of 5.7 ppm · m and 2.4 ppm · m, respectively.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/104362

DOI

https://doi.org/10.15278/isms.2019.FB02

Copyright and License Information

Copyright 2019 Kevin C. Cossel

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