TIME AND SPATIALLY-RESOLVED LIF OF OH A(2)SIGMA-PRESSURE FLAMES USINGPICOSECOND EXCITATION((UPSILON'=1) IN ATMOSPHERIC)

One dimensional imaging of fluorescence lifetimes was performed direct ly for the first time in a premixed, atmospheric-pressure ethylene/air flame. A picosecond laser system based on the microscope-DFDL (Distri buted-Feedback Dye Laser) was used for excitation of OH. The method in volves imaging a section of the flame onto the streak camera and evalu ating a series of windows, each with a certain number of channels of t he CCD-multichannel plate. In this way, changes in quenching efficienc y can be monitored along a horizontal line through the flame. These di rect lifetime measurements confirm the observations of relative lifeti mes previously obtained for this flame by saturated 2D-LIF.