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Comprehensive CO detection in flames using femtosecond two-photon laser-induced fluorescence

Li, Bo LU ; Li, Xiaofeng; Zhang, Dayuan; Gao, Qiang LU ; Yao, Mingfa and Li, Zhongshan LU (2017) In Optics Express 25(21). p.25809-25818
Abstract

We demonstrate a femtosecond two-photon laser-induced fluorescence (fs-TPLIF) technique for sensitive CO detection, using a 230 nm pulse of 9 µJ and 45 fs. The advantages of fs-TPLIF in excitation of molecular species were analyzed. Spectra of CO fs-TPLIF were recorded in stable laminar flames spatially resolved across the flame front. A hot band (1, n) together with the conventional band (0, n) of the B→A transitions were observed in the burned zone and attributed to the broadband nature of the fs excitation. The CO fs-TPLIF signal recorded across the focal point of the excitation beam shows a relatively flat intensity distribution despite of the steep... (More)

We demonstrate a femtosecond two-photon laser-induced fluorescence (fs-TPLIF) technique for sensitive CO detection, using a 230 nm pulse of 9 µJ and 45 fs. The advantages of fs-TPLIF in excitation of molecular species were analyzed. Spectra of CO fs-TPLIF were recorded in stable laminar flames spatially resolved across the flame front. A hot band (1, n) together with the conventional band (0, n) of the B→A transitions were observed in the burned zone and attributed to the broadband nature of the fs excitation. The CO fs-TPLIF signal recorded across the focal point of the excitation beam shows a relatively flat intensity distribution despite of the steep laser intensity variation, which is beneficial for CO imaging in contrast to nanosecond and picosecond TPLIF. This phenomenon can be explained by photoionization, which over the short pulse duration dominates the population depletion of the excited B state due to the high peak power, but only contributes in total a negligible X state depletion due to the low pulse energy. Single-shot CO fs-TPLIF images in methane/air flames were recorded by imaging the broadband fluorescence. The results indicate that fs-TPLIF is a promising tool for CO imaging in flames.

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organization
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type
Contribution to journal
publication status
published
subject
in
Optics Express
volume
25
issue
21
pages
10 pages
publisher
OSA
external identifiers
  • scopus:85031317258
  • wos:000413103300087
ISSN
1094-4087
DOI
10.1364/OE.25.025809
language
English
LU publication?
yes
id
df9e5076-be5e-4880-9f8d-48972f2191c6
date added to LUP
2017-10-26 08:48:07
date last changed
2018-01-16 13:24:16
@article{df9e5076-be5e-4880-9f8d-48972f2191c6,
  abstract     = {<p>We demonstrate a femtosecond two-photon laser-induced fluorescence (fs-TPLIF)      technique      for sensitive CO detection, using a 230 nm pulse of 9 µJ and 45 fs. The      advantages      of fs-TPLIF in excitation of molecular species were analyzed. Spectra      of CO      fs-TPLIF were recorded in stable laminar flames spatially resolved across the      flame      front. A hot band (1, n) together with the conventional band (0, n) of the      B→A      transitions were observed in the burned zone and attributed to the broadband      nature      of the fs excitation. The CO fs-TPLIF signal recorded across the focal point      of      the excitation beam shows a relatively flat intensity distribution despite of      the      steep laser intensity variation, which is beneficial for CO imaging in contrast      to      nanosecond and picosecond TPLIF. This phenomenon can be explained by photoionization,      which      over the short pulse duration dominates the population depletion of the excited      B      state due to the high peak power, but only contributes in total a negligible X      state      depletion due to the low pulse energy. Single-shot CO fs-TPLIF images in methane/air      flames      were recorded by imaging the broadband fluorescence. The results indicate      that      fs-TPLIF is a promising tool for CO imaging in flames.</p>},
  author       = {Li, Bo and Li, Xiaofeng and Zhang, Dayuan and Gao, Qiang and Yao, Mingfa and Li, Zhongshan},
  issn         = {1094-4087},
  language     = {eng},
  month        = {10},
  number       = {21},
  pages        = {25809--25818},
  publisher    = {OSA},
  series       = {Optics Express},
  title        = {Comprehensive CO detection in flames using femtosecond two-photon laser-induced fluorescence},
  url          = {http://dx.doi.org/10.1364/OE.25.025809},
  volume       = {25},
  year         = {2017},
}