We demonstrate hybrid femtosecond/picosecond (fs/ps) coherent anti-Stokes Raman scattering for high-speed thermometry in unsteady high-temperature flames, including successful comparisons with a time- and frequency- resolved theoretical model. After excitation of the vibrational manifold with broadband pump and Stokes beams, the Raman coherence is probed using a frequency-narrowed probe beam that is time delayed to suppress the nonresonant background by 2 orders of magnitude. Experimental spectra were obtained at in steady and pulsed –air flames and exhibit a temperature precision of 2.2% and an accuracy of 3.3% up to . Strategies for real-time gas-phase thermometry in high-temperature flames are also discussed, along with implications for kilohertz-rate measurements in practical combustion systems.
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