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Fourier‐based approach to overcome anomalies in high‐resolution spectra of vibrational CARS measurements of gases
Author(s) -
Nordström E.,
Bengtsson P.E.,
Marrocco M.
Publication year - 2014
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4464
Subject(s) - grating , raman spectroscopy , dispersion (optics) , spectral resolution , spectral line , optics , laser , raman scattering , fourier transform , resolution (logic) , chemistry , modulation (music) , analytical chemistry (journal) , physics , acoustics , quantum mechanics , astronomy , artificial intelligence , computer science , chromatography
In this work, we report on an unconventional experimental procedure useful for thermometric measurements on the basis of high‐resolution vibrational coherent anti‐Stokes Raman scattering (CARS) generated using conventional lasers. The high spectral dispersion of 0.02 cm −1 /pixel is achieved by means of some specific spectral arrangements (single‐mode pump laser and diffraction grating providing spectra at the sixth order) and is further strengthened by the use of a relay lens system mounted before the charge‐coupled device camera. Surprisingly, at the high spectral dispersion of our measurements, a significant and persistent thermometric inaccuracy is observed. The effect arises from an inevitable spectral modulation of defined frequency hidden in the main CARS signal of the gas under study, and to secure a good thermometric evaluation, we describe a Fourier approach that is experimentally demonstrated for the typical nitrogen CARS spectrum measured at room temperature. Copyright © 2014 John Wiley & Sons, Ltd.