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Online Raman spectroscopy for quantitative detection and characterization of aerosolized soot

Bergqvist, Saga LU ; Bengtsson, Per Erik LU orcid and Le, Kim Cuong LU orcid (2024) In Optics Express 32(16). p.28681-28694
Abstract

Ex-situ Raman spectroscopy is a well-established method for the structural characterization of soot but necessitates a sampling step before analysis is made. This work studied the potential to perform Raman spectroscopic measurements of soot directly in the combustion exhaust gases, i.e., online Raman measurements. Two types of soot were produced from a Mini-CAST soot generator, one immature with high organic content and one mature with low organic content. Also, two different measurement configurations were used, a 90-degree and a backscattering configuration, as well as different polarization combinations of the laser radiation and the detected photons. Spectrally resolved Raman signals were successfully recorded and analyzed for the... (More)

Ex-situ Raman spectroscopy is a well-established method for the structural characterization of soot but necessitates a sampling step before analysis is made. This work studied the potential to perform Raman spectroscopic measurements of soot directly in the combustion exhaust gases, i.e., online Raman measurements. Two types of soot were produced from a Mini-CAST soot generator, one immature with high organic content and one mature with low organic content. Also, two different measurement configurations were used, a 90-degree and a backscattering configuration, as well as different polarization combinations of the laser radiation and the detected photons. Spectrally resolved Raman signals were successfully recorded and analyzed for the two soot types showing differences between the characteristic D and G peaks as well as the photoluminescence signal. Additionally, the Raman cross section was determined for both soot types and found to be higher for the immature soot. It was also found that a horizontally polarized laser excitation and a 90-degree collection angle had the best potential to reduce the interference from ambient gases. This study can be seen as a first step towards remote sensing of soot.

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author
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organization
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type
Contribution to journal
publication status
published
subject
in
Optics Express
volume
32
issue
16
pages
14 pages
publisher
Optical Society of America
external identifiers
  • scopus:85199959457
ISSN
1094-4087
DOI
10.1364/OE.527414
language
English
LU publication?
yes
id
b7e38057-d542-455c-970c-68a9f13303e9
date added to LUP
2024-09-26 15:07:23
date last changed
2024-09-26 15:08:06
@article{b7e38057-d542-455c-970c-68a9f13303e9,
  abstract     = {{<p>Ex-situ Raman spectroscopy is a well-established method for the structural characterization of soot but necessitates a sampling step before analysis is made. This work studied the potential to perform Raman spectroscopic measurements of soot directly in the combustion exhaust gases, i.e., online Raman measurements. Two types of soot were produced from a Mini-CAST soot generator, one immature with high organic content and one mature with low organic content. Also, two different measurement configurations were used, a 90-degree and a backscattering configuration, as well as different polarization combinations of the laser radiation and the detected photons. Spectrally resolved Raman signals were successfully recorded and analyzed for the two soot types showing differences between the characteristic D and G peaks as well as the photoluminescence signal. Additionally, the Raman cross section was determined for both soot types and found to be higher for the immature soot. It was also found that a horizontally polarized laser excitation and a 90-degree collection angle had the best potential to reduce the interference from ambient gases. This study can be seen as a first step towards remote sensing of soot.</p>}},
  author       = {{Bergqvist, Saga and Bengtsson, Per Erik and Le, Kim Cuong}},
  issn         = {{1094-4087}},
  language     = {{eng}},
  number       = {{16}},
  pages        = {{28681--28694}},
  publisher    = {{Optical Society of America}},
  series       = {{Optics Express}},
  title        = {{Online Raman spectroscopy for quantitative detection and characterization of aerosolized soot}},
  url          = {{http://dx.doi.org/10.1364/OE.527414}},
  doi          = {{10.1364/OE.527414}},
  volume       = {{32}},
  year         = {{2024}},
}