Abstract
A coherent interference with multiplex CARS signals is observed. This effect appears when coal fly ash particles are injected into the combustion flow being probed. The interference has the same spectral characteristics of the Stokes broadband dye laser shifted to anti-Stokes frequencies and is correlated with weak particle-induced laser breakdown. Analysis indicates the phenomenon is due to the enhancement of the nonresonant susceptibility in the small volume of the discharge plasma.