Three-color vibrational CARS thermometry of fuel-rich ethylene/air flames using a potassium gadolinium tungstate Raman-active crystal as a source of narrowband probe radiation

Christian Meißner; Johannes W Tröger; Dimitrii N Kozlov; Frank Beyrau; Thomas Seeger

doi:10.1364/AO.56.000E77

Three-color vibrational CARS thermometry of fuel-rich ethylene/air flames using a potassium gadolinium tungstate Raman-active crystal as a source of narrowband probe radiation

Appl Opt. 2017 Apr 10;56(11):E77-E83. doi: 10.1364/AO.56.000E77.

Authors

Christian Meißner, Johannes W Tröger, Dimitrii N Kozlov, Frank Beyrau, Thomas Seeger

PMID: 28414345
DOI: 10.1364/AO.56.000E77

Abstract

Three-color broadband vibrational coherent anti-Stokes Raman scattering (CARS) temperature measurements were carried out in laminar fuel-rich sooting ethylene/air flames. Stimulated Raman scattering (SRS) of a picosecond pump laser pulse in a Raman-active potassium gadolinium tungstate [KGd(WO₄)₂] crystal was employed as a source of narrowband probe radiation. In the three-color CARS experiment, this wavelength-shifted radiation enables N₂-based vibrational CARS temperature measurements in sooting flames free of the signal interference with the absorption/emission bands of the flame intermediate radicals C₂. Spatial temperature profiles for different fuel-rich atmospheric pressure ethylene/air flames are presented in comparison with the results of two-color broadband vibrational and dual-broadband pure rotational CARS temperature measurements. The comparison shows the suitability of the three-color CARS measurement technique employing the KGd(WO₄)₂ crystal for accurate, C₂ interference-free, temperature measurements in sooting flames.