Detection of OH in flames by using polarization spectroscopy.

The potentials of polarization spectroscopy in combustion studies are reported. This well-established technique of nonlinear laser spectroscopy is applied to the detection of OH molecules in a premixed acetylene-oxygen and a propane-air flame. The polarization spectrum is recorded in the A (2)Sigma-X(2)Pi(0, 0) band. The spatial distribution of OH is measured in the flames. The saturation of the signal as a function of the laser pulse intensity is also investigated.