APPLICATION OF TUNABLE EXCIMER LASERS TO COMBUSTION DIAGNOSTICS - A REVIEW

Tunable excimer lasers are being used to produce species-, space-, and time-resolved images of complex gaseous media. These media may be ana lyzed for composition, density, temperature, or flow velocities. The t echniques are, in general, highly selective, sensitive, and nonintrusi ve and are being made possible by recent technological developments in these UV lasers and in intensified cameras, imaging spectrographs, an d fast digital image processing. We describe the needs for laser diagn ostics in combustion, the physical mechanisms, the relevant spectrosco py, typical experimental setups, and equipment considerations. Precisi on and accuracy are discussed on the basis of some simple, but realist ic, calculations intended to guide the experimentalist in design consi derations and to reveal potential sources of errors in the often diffi cult conversion of raw data to values for such quantitative parameters as densities or temperatures. Finally we present an overview of previ ous results, select some examples that show the power of tunable excim er laser diagnostics in combustion, and present some suggestions for f uture directions. (C) 1997 Optical Society of America.