THE APPLICATION OF A RAMAN-SHIFTED TUNABLE KRF EXCIMER LASER FOR LASER-INDUCED FLUORESCENCE COMBUSTION DIAGNOSTICS

Four wavelength extensions have been investigated by stimulated Raman scattering in hydrogen or deuterium gas of the 248 nm fundamental output of a narrow-band tunable KrF excimer laser. They have been used to acquire laser-induced fluorescence spectra of NO and OH in flames at atmospheric pressure. NO is detected in relatively high rotational states within the gamma-band electronic system at 225 nm. OH was excited at 291.5 nm in the (1-0), at 313 nm in the (1-1) and at 268.5 nm in the predissociative (3-1) band of the 2SIGMA-2PI electronic band system, respectively. Prospects of 2D imaging for concentration and temperature measurements in flames using these wavelength extensions are discussed.