Engineering Commons^™

Hybrid Femtosecond/Picosecond Coherent Anti-Stokes Raman Scattering For High-Speed Gas-Phase Thermometry, Joseph D. Miller, Mikhail N. Slipchenko, Terrence R. Meyer, Hans U. Stauffer, James R. Goird

Terrence R Meyer

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 frequencyresolved theoretical model. After excitation of the N2 vibrational manifold with 100 fs broadband pump and Stokes beams, the Raman coherence is probed using a frequency-narrowed 2:5 ps probe beam that is time delayed to suppress the nonresonant background by 2 orders of magnitude. Experimental spectra were obtained at 500 Hz in steady and pulsed H2–air flames and exhibit a temperature precision of 2.2% and an accuracy of 3.3% up to 2400 K. Strategies for real-time gas-phase …