Abbas, M.A.; Dijk, L.; Jahromi, K.E.; Nematollahi, M.; Harren, F.J.M.; Khodabakhsh, A. Broadband Time-Resolved Absorption and Dispersion Spectroscopy of Methane and Ethane in a Plasma Using a Mid-Infrared Dual-Comb Spectrometer. Sensors2020, 20, 6831.
Abbas, M.A.; Dijk, L.; Jahromi, K.E.; Nematollahi, M.; Harren, F.J.M.; Khodabakhsh, A. Broadband Time-Resolved Absorption and Dispersion Spectroscopy of Methane and Ethane in a Plasma Using a Mid-Infrared Dual-Comb Spectrometer. Sensors 2020, 20, 6831.
Abbas, M.A.; Dijk, L.; Jahromi, K.E.; Nematollahi, M.; Harren, F.J.M.; Khodabakhsh, A. Broadband Time-Resolved Absorption and Dispersion Spectroscopy of Methane and Ethane in a Plasma Using a Mid-Infrared Dual-Comb Spectrometer. Sensors2020, 20, 6831.
Abbas, M.A.; Dijk, L.; Jahromi, K.E.; Nematollahi, M.; Harren, F.J.M.; Khodabakhsh, A. Broadband Time-Resolved Absorption and Dispersion Spectroscopy of Methane and Ethane in a Plasma Using a Mid-Infrared Dual-Comb Spectrometer. Sensors 2020, 20, 6831.
Abstract
Conventional mechanical Fourier Transform Spectrometers (FTS) are able to simultaneously measure absorption and dispersion spectra of gas-phase samples. However, they usually need very long measurement times to achieve time-resolved spectra with a good spectral and temporal resolution. Here, we present a mid-infrared dual-comb-based FTS in an asymmetric configuration, providing broadband absorption and dispersion spectra with a spectral resolution of 5 GHz, a temporal resolution of 20 μs, and a total measurement time of a few minutes. We used the dual-comb spectrometer to monitor the reaction dynamics of methane and ethane in an electrical plasma discharge. We observed ethane/methane formation as a recombination reaction of hydrocarbon radicals in the discharge in various static and dynamic conditions. The results demonstrate a new analytical approach for measuring fast molecular absorption and dispersion changes and monitoring fast dynamics of chemical reactions, which can be interesting for chemical kinetic research and particularly for the combustion and plasma analysis community.
Keywords
dual frequency comb spectroscopy; mid-infrared absorption and dispersion spectroscopy; electrical discharge plasma; time-resolved plasma kinetics
Subject
PHYSICAL SCIENCES, Atomic & Molecular Physics
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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