Investigation of two-color polarization spectroscopy (TCPS) and two-color six-wave mixing (TC-SWM) for detection of atomic hydrogen

(2005) by the Western States Section/Combustion Institute. All rights reserved. We report results from an investigation of the two-color polarization spectroscopy (TC-PS) and two-color six-wave mixing (TC-SWM) techniques for the measurement of atomic hydrogen in flames. The 243-nm two-photon pumping of 1S-2S transition of the H-atom was followed by single-photon probing of the 2S-3P transition at 656 nm. Necessary laser radiation was generated using two distributed feedback dye lasers (DFDLs) pumped by two regeneratively amplified, picosecond, Nd:YAG lasers. The DFDL pulses are nearly Fourier transform limited and have a pulse width of approximately 80 ps. The effects of pump and probe beam polarizations on the TC-PS and TC-SWM signals were studied in detail. The collisional dynamics of the H(2l) level were also investigated in an atmospheric-pressure hydrogenair flame by scanning the time delay between the pump and probe pulses. An increase in signal intensity of approximately 100 was observed in the TC-SWM geometry as compared to the TC-PS geometry.

Fall Technical Meeting of the Western States Section of the Combustion Institute 2005, WSS/CI 2005 Fall Meeting

Investigation of two-color polarization spectroscopy (TCPS) and two-color six-wave mixing (TC-SWM) for detection of atomic hydrogen Conference Paper