Direct measurement of OH local concentration in a flame from the fluorescence induced by a single laser pulse

An alternative to the saturation approach is proposed to avoid the quenching dependence of the fluorescence intensity. The method allows direct absolute measurement of the local number density from a single laser shot. A mean quenching cross section of 5 x 10(-19) m(2) is deduced from the experiments, and a OH concentration profile through the flame is given.