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Single-shot fs/ns rotational CARS for temporally and spectrally resolved gas-phase diagnostics

Hosseinnia, Ali LU orcid ; Ruchkina, Maria LU ; Ding, Pengji LU orcid ; Bood, Joakim LU and Bengtsson, Per Erik LU orcid (2021) In Proceedings of the Combustion Institute 38(1). p.1843-1850
Abstract

We report thermometry and new Raman linewidth data using a novel method for time-domain rotational coherent anti-Stokes Raman spectroscopy (RCARS) on single-shot basis. The coherences are generated by two fs pulses and probed by a ns pulse. The resulting signal is detected using a combined spectrograph/streak camera setup with high spectral and temporal resolution. Rotational CARS spectrograms of nitrogen (N2), ethylene (C2H4), ethane (C2H6), and argon (Ar) are demonstrated at ambient condition. Self-broadened N2–N2 S-branch Raman linewidths were measured on single-shot basis and show excellent agreement with literature values. Furthermore, Raman linewidths of... (More)

We report thermometry and new Raman linewidth data using a novel method for time-domain rotational coherent anti-Stokes Raman spectroscopy (RCARS) on single-shot basis. The coherences are generated by two fs pulses and probed by a ns pulse. The resulting signal is detected using a combined spectrograph/streak camera setup with high spectral and temporal resolution. Rotational CARS spectrograms of nitrogen (N2), ethylene (C2H4), ethane (C2H6), and argon (Ar) are demonstrated at ambient condition. Self-broadened N2–N2 S-branch Raman linewidths were measured on single-shot basis and show excellent agreement with literature values. Furthermore, Raman linewidths of N2 S-branch perturbed by C2H4 and C2H6 were measured for the first time. The time-resolved approach was also utilized to separate complex spectra from a mixture of species through their difference in coherence lifetimes. Since the Raman coherences decay much faster for both ethane and ethylene than for nitrogen, pure nitrogen spectra could be obtained by analyzing only the temporal tail of the signal. Moreover, a model for time-resolved RCARS of N2 was developed, which employs the single-shot measured Raman linewidths to calculate the corresponding spectro-temporally resolved spectrograms at different temperatures. The model was used to evaluate the temperature from single-shot data of an N2/C2H6 mixture, showing very high accuracy. The demonstrated method constitutes an essential improvement for single-shot thermometry as it does not require pre-knowledge about collider species concentrations and their impact on linewidths.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Coherence lifetime, Raman linewidths, Rotational CARS, Single-shot thermometry, Ultrafast spectroscopy
in
Proceedings of the Combustion Institute
volume
38
issue
1
pages
8 pages
publisher
Elsevier
external identifiers
  • scopus:85092487596
ISSN
1540-7489
DOI
10.1016/j.proci.2020.09.010
language
English
LU publication?
yes
id
7c5349af-b4c1-4dac-9234-b01bd14aa396
date added to LUP
2021-01-08 13:10:35
date last changed
2022-04-26 23:08:38
@article{7c5349af-b4c1-4dac-9234-b01bd14aa396,
  abstract     = {{<p>We report thermometry and new Raman linewidth data using a novel method for time-domain rotational coherent anti-Stokes Raman spectroscopy (RCARS) on single-shot basis. The coherences are generated by two fs pulses and probed by a ns pulse. The resulting signal is detected using a combined spectrograph/streak camera setup with high spectral and temporal resolution. Rotational CARS spectrograms of nitrogen (N<sub>2</sub>), ethylene (C<sub>2</sub>H<sub>4</sub>), ethane (C<sub>2</sub>H<sub>6</sub>), and argon (Ar) are demonstrated at ambient condition. Self-broadened N<sub>2</sub>–N<sub>2</sub> S-branch Raman linewidths were measured on single-shot basis and show excellent agreement with literature values. Furthermore, Raman linewidths of N<sub>2</sub> S-branch perturbed by C<sub>2</sub>H<sub>4</sub> and C<sub>2</sub>H<sub>6</sub> were measured for the first time. The time-resolved approach was also utilized to separate complex spectra from a mixture of species through their difference in coherence lifetimes. Since the Raman coherences decay much faster for both ethane and ethylene than for nitrogen, pure nitrogen spectra could be obtained by analyzing only the temporal tail of the signal. Moreover, a model for time-resolved RCARS of N<sub>2</sub> was developed, which employs the single-shot measured Raman linewidths to calculate the corresponding spectro-temporally resolved spectrograms at different temperatures. The model was used to evaluate the temperature from single-shot data of an N<sub>2</sub>/C<sub>2</sub>H<sub>6</sub> mixture, showing very high accuracy. The demonstrated method constitutes an essential improvement for single-shot thermometry as it does not require pre-knowledge about collider species concentrations and their impact on linewidths.</p>}},
  author       = {{Hosseinnia, Ali and Ruchkina, Maria and Ding, Pengji and Bood, Joakim and Bengtsson, Per Erik}},
  issn         = {{1540-7489}},
  keywords     = {{Coherence lifetime; Raman linewidths; Rotational CARS; Single-shot thermometry; Ultrafast spectroscopy}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{1843--1850}},
  publisher    = {{Elsevier}},
  series       = {{Proceedings of the Combustion Institute}},
  title        = {{Single-shot fs/ns rotational CARS for temporally and spectrally resolved gas-phase diagnostics}},
  url          = {{http://dx.doi.org/10.1016/j.proci.2020.09.010}},
  doi          = {{10.1016/j.proci.2020.09.010}},
  volume       = {{38}},
  year         = {{2021}},
}