Abstract

Fluorescence quenching lifetimes for many key flame species, such as OH, CH, NO, are generally of the order of nanoseconds or less at atmospheric and higher pressures. These data are needed for obtaining accurate species concentrations. However, lifetimes on this scale can only be determined directly with an ultrashort pulsed laser system coupled with the appropriate detection techniques. We have, therefore, constructed a dye laser system (Fig. 1) based on the distributed feedback (DF) principle.¹ This type of system has the advantage that picosecond UV pulses can be attained with energies sufficient for subsequent streak camera detection using only one pump laser. Pulses in the required wavelength range are obtained by selecting the appropriate dye and adjusting the composition of the solvent mixture in the DFDL cuvette.²

© 1988 Optical Society of America