SATURATED 2D-LIF OF OH AND 2D DETERMINATION OF EFFECTIVE COLLISIONAL LIFETIMES IN ATMOSPHERIC-PRESSURE FLAMES

Saturation of two-dimensional laser-induced fluorescence is demonstrated using the coincidence between the strong 0-0 vibrational transition of OH around 308 nm and the emission of a tunable XeCl excimer laser. The 2D images were insensitive to variations in the laser power, implying reduced sensitivity to quenching processes. The ratio of the 2D images in the linear and saturated regimes show two-dimensional variations in the saturation intensity. Since saturation intensity is proportional to the quenching rate, this novel method allows one to check for variations in collisional lifetimes across the flame.