Mid-Infrared Generated Laser-Induced Grating Signals in Methane-Containing Gas Mixtures as Indicators of Composition, Pressure, and Temperature
(2024) In Applied Spectroscopy 78(4).- Abstract
The present work is aimed at studying how spatially periodic modulations of the refractive index of the medium, i.e., laser-induced gratings (LIGs), generated in a gas mixture containing methane (CH4) by nanosecond pulses of resonant mid-infrared laser radiation, can be used to measure various gas parameters. It is investigated to what extent the temporal profiles of the LIG signals, recorded as the power of the diffracted by LIGs continuous wave probe radiation, are specific to the composition, pressure, and temperature of a selected buffer gas. This specificity is illustrated by the LIG signal profiles recorded in the experiments in different gas mixtures under various conditions. Experimental data show that large LIG... (More)
The present work is aimed at studying how spatially periodic modulations of the refractive index of the medium, i.e., laser-induced gratings (LIGs), generated in a gas mixture containing methane (CH4) by nanosecond pulses of resonant mid-infrared laser radiation, can be used to measure various gas parameters. It is investigated to what extent the temporal profiles of the LIG signals, recorded as the power of the diffracted by LIGs continuous wave probe radiation, are specific to the composition, pressure, and temperature of a selected buffer gas. This specificity is illustrated by the LIG signal profiles recorded in the experiments in different gas mixtures under various conditions. Experimental data show that large LIG signals can be obtained even in mixtures with CH4 concentrations as low as ∼100 parts per million due to the strong absorption of the excitation light and subsequent rapid, highly exothermic, and partner-dependent collisional energy exchange of the laser-excited molecules with the environment. These two factors ensure high LIG generation efficiency by a small number of CH4 molecules and high sensitivity of signal strength and profile to variations of gas parameters.
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- author
- Sahlberg, Anna Lena LU ; Hot, Dina LU ; Li, Zhongshan LU and Kozlov, Dimitrii
- organization
- publishing date
- 2024
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- gas sensing, laser-induced grating, LIG, methane detection, mid-infrared excitation, Nonlinear optical spectroscopy
- in
- Applied Spectroscopy
- volume
- 78
- issue
- 4
- pages
- 423 pages
- publisher
- Society for Applied Spectroscopy
- external identifiers
-
- pmid:38373441
- scopus:85186480665
- ISSN
- 0003-7028
- DOI
- 10.1177/00037028241230340
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © The Author(s) 2024.
- id
- 94732abc-5102-49e3-8850-6e2a761aecd9
- date added to LUP
- 2024-03-20 13:27:54
- date last changed
- 2024-04-17 13:02:13
@article{94732abc-5102-49e3-8850-6e2a761aecd9, abstract = {{<p>The present work is aimed at studying how spatially periodic modulations of the refractive index of the medium, i.e., laser-induced gratings (LIGs), generated in a gas mixture containing methane (CH<sub>4</sub>) by nanosecond pulses of resonant mid-infrared laser radiation, can be used to measure various gas parameters. It is investigated to what extent the temporal profiles of the LIG signals, recorded as the power of the diffracted by LIGs continuous wave probe radiation, are specific to the composition, pressure, and temperature of a selected buffer gas. This specificity is illustrated by the LIG signal profiles recorded in the experiments in different gas mixtures under various conditions. Experimental data show that large LIG signals can be obtained even in mixtures with CH<sub>4</sub> concentrations as low as ∼100 parts per million due to the strong absorption of the excitation light and subsequent rapid, highly exothermic, and partner-dependent collisional energy exchange of the laser-excited molecules with the environment. These two factors ensure high LIG generation efficiency by a small number of CH<sub>4</sub> molecules and high sensitivity of signal strength and profile to variations of gas parameters.</p>}}, author = {{Sahlberg, Anna Lena and Hot, Dina and Li, Zhongshan and Kozlov, Dimitrii}}, issn = {{0003-7028}}, keywords = {{gas sensing; laser-induced grating; LIG; methane detection; mid-infrared excitation; Nonlinear optical spectroscopy}}, language = {{eng}}, number = {{4}}, publisher = {{Society for Applied Spectroscopy}}, series = {{Applied Spectroscopy}}, title = {{Mid-Infrared Generated Laser-Induced Grating Signals in Methane-Containing Gas Mixtures as Indicators of Composition, Pressure, and Temperature}}, url = {{http://dx.doi.org/10.1177/00037028241230340}}, doi = {{10.1177/00037028241230340}}, volume = {{78}}, year = {{2024}}, }