Directly-excited laser-induced thermal grating spectroscopy and thermometry with carbon dioxide vibrational transition
Song, Zihao LU ; Zhu, Ning ; Wang, Weitian ; Sahlberg, Anna Lena LU
and Chao, Xing
(2024)
In Measurement Science and Technology
35(9).
- Abstract
Laser-induced thermal grating spectroscopy (LITGS) has been proved for accurate thermometry and measurement of energy transfer processes in molecules. While electronic transitions are often used for excitation in previous LITGS works, here we report laser-induced thermal gratings formed by direct excitation of CO2 with an infrared (IR) laser at wavelength near 2 μm, with which high signal-to-noise ratio LITGS signals are generated (SNR ∼ 300 at room temperature). A theoretical LITGS model assuming a ‘two-steps’ energy transfer process is used to describe the recorded signal waveform, with relative fitting residuals of less than 10%. Quantitative thermometry is performed in CO2 gas flows between 293 K and 420 K,... (More)
Laser-induced thermal grating spectroscopy (LITGS) has been proved for accurate thermometry and measurement of energy transfer processes in molecules. While electronic transitions are often used for excitation in previous LITGS works, here we report laser-induced thermal gratings formed by direct excitation of CO2 with an infrared (IR) laser at wavelength near 2 μm, with which high signal-to-noise ratio LITGS signals are generated (SNR ∼ 300 at room temperature). A theoretical LITGS model assuming a ‘two-steps’ energy transfer process is used to describe the recorded signal waveform, with relative fitting residuals of less than 10%. Quantitative thermometry is performed in CO2 gas flows between 293 K and 420 K, with a relative uncertainty of 1.6% and a precision of 1.1% defined as the 1-σ standard deviation of 30 repeated measurement. Furthermore, the time constants of vibrational energy transfer at different temperatures are extracted from the temporal signal waveform with a precision better than 80 ns, and the measured results are consistent with the simulation using a detailed vibrational energy transfer model. These results demonstrate IR LITGS as a potential tool for spatially-resolved measurement of the thermophysical properties of fluids, as well as molecular vibrational energy transfer processes.
(Less)
- author
- Song, Zihao
LU
; Zhu, Ning
; Wang, Weitian
; Sahlberg, Anna Lena
LU
and Chao, Xing
- organization
- publishing date
- 2024-09
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- CO vibrational energy transfer measurement, gas thermometry, Infrared laser-induced thermal grating spectroscopy
- in
- Measurement Science and Technology
- volume
- 35
- issue
- 9
- article number
- 095208
- publisher
- IOP Publishing
- external identifiers
-
- scopus:85197589768
- ISSN
- 0957-0233
- DOI
- 10.1088/1361-6501/ad56aa
- language
- English
- LU publication?
- yes
- id
- c26c89a2-78b5-4130-ae95-29787a7c678d
- date added to LUP
- 2024-09-09 16:16:15
- date last changed
- 2024-09-27 09:25:15
@article{c26c89a2-78b5-4130-ae95-29787a7c678d,
abstract = {{<p>Laser-induced thermal grating spectroscopy (LITGS) has been proved for accurate thermometry and measurement of energy transfer processes in molecules. While electronic transitions are often used for excitation in previous LITGS works, here we report laser-induced thermal gratings formed by direct excitation of CO<sub>2</sub> with an infrared (IR) laser at wavelength near 2 μm, with which high signal-to-noise ratio LITGS signals are generated (SNR ∼ 300 at room temperature). A theoretical LITGS model assuming a ‘two-steps’ energy transfer process is used to describe the recorded signal waveform, with relative fitting residuals of less than 10%. Quantitative thermometry is performed in CO<sub>2</sub> gas flows between 293 K and 420 K, with a relative uncertainty of 1.6% and a precision of 1.1% defined as the 1-σ standard deviation of 30 repeated measurement. Furthermore, the time constants of vibrational energy transfer at different temperatures are extracted from the temporal signal waveform with a precision better than 80 ns, and the measured results are consistent with the simulation using a detailed vibrational energy transfer model. These results demonstrate IR LITGS as a potential tool for spatially-resolved measurement of the thermophysical properties of fluids, as well as molecular vibrational energy transfer processes.</p>}},
author = {{Song, Zihao and Zhu, Ning and Wang, Weitian and Sahlberg, Anna Lena and Chao, Xing}},
issn = {{0957-0233}},
keywords = {{CO vibrational energy transfer measurement; gas thermometry; Infrared laser-induced thermal grating spectroscopy}},
language = {{eng}},
number = {{9}},
publisher = {{IOP Publishing}},
series = {{Measurement Science and Technology}},
title = {{Directly-excited laser-induced thermal grating spectroscopy and thermometry with carbon dioxide vibrational transition}},
url = {{http://dx.doi.org/10.1088/1361-6501/ad56aa}},
doi = {{10.1088/1361-6501/ad56aa}},
volume = {{35}},
year = {{2024}},
}