2020/02/10 by Nils Torge Mecker, Trevor L. Courtney, Brian D. Patterson +5
Biochemistry, Genetics and Molecular Biology · Chemistry · Physics and Astronomy · #Chemistry #Femtosecond #Laser #Laser-Matter Interactions and Applications #Materials science #Nitrogen #Optics #Physics #Picosecond #Raman spectroscopy #Spectroscopy #Spectroscopy Techniques in Biomedical and Chemical Research #Spectroscopy and Laser Applications #physics.ins-det #physics.optics
paper · pdf · doi:10.1364/josab.383575
published as Journal of the Optical Society of America B 37 (4) 2020
openalex publication_date 2020/02/10 · openalex created_date 2020/02/24 · arxiv created 2020/09/03 · arxiv updated 2020/09/04 · openalex updated_date 2026/08/05
We demonstrate the use of hybrid rotational femtosecond/picosecond (fs/ps) coherent anti-Stokes Raman spectroscopy (HR-CARS) as a technique for temperature measurements in nitrogen gas at high pressures and temperatures. A broadband pulse shaper-adjusted 42 fs pulse interacts with a narrow-bandwidth, frequency-upconverted 5.5 ps pulse in a cell containing <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">N</mml:mi> </mml:mrow> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>2</mml:mn> </mml:mrow> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> at pressures of 1–70 atm and temperatures of 300–1000 K. A computational code is used to model spectra and fit experimental results to obtain best-fit temperatures. We demonstrate good qualitative fits as well as good accuracy and precision between thermocouple measured and best-fit temperatures over the explored pressure and temperature regimes. The overall average percentage temperature difference between thermocouple measurements and best-fit temperatures is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo>−</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>0</mml:mn> </mml:mrow> </mml:mrow> <mml:mo>.</mml:mo> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>3</mml:mn> </mml:mrow> </mml:mrow> <mml:mi mathvariant="normal">%</mml:mi> </mml:math> with a standard deviation of 7.1%, showing the suitability of HR-CARS for characterizing high-pressure and -temperature environments.