A procedure is proposed, denoted as the corrected laser-induced fluorescence (LIF) method, that reduces the error associated with the unavoidable photodissociation of O2 molecules that has limited the measurement of oxygen–atom concentrations in the past. Two different laser intensities are employed, and the two signals that are obtained with two-photon LIF diagnostics are used to correct for the photolysis error. We measured oxygen–atom concentrations using this method at 33 locations in lean and rich flames. Results are compared with values determined by use of two independent techniques: the partial equilibrium method and equilibrium calculations. The measurements also quantify the shot noise, the photolysis errors, and the critical laser intensity required to avoid photolysis errors.
© 2001 Optical Society of America
Original Manuscript: March 5, 2001
Revised Manuscript: June 6, 2001
Published: October 20, 2001
Franklin H. Myhr and James F. Driscoll, "Oxygen–atom concentrations measured in flames: a method to improve the accuracy of laser-induced fluorescence diagnostics," Appl. Opt. 40, 5388-5394 (2001)