Abstract

The recently developed Raman excitation plus laser-induced electronic fluorescence (RELIEF) method of tagging oxygen molecules provides a powerful tool for studying turbulent structure in high-speed air flows. The advantage comparing with other flow diagnosis methods is that a nonintrusive, instantaneous structure of high-sped flow can be obtained by this new technique. For this method, it is necessary to pump oxygen molecules up to vibrational exciting states by two simultaneously pulsed high-power lasers whose frequencies differ by the vibrational frequency of oxygen(1555cm^-1). The wavelengths of the two lasers are 532nm and 580nm, respectively, which are usually chosen as pump source for tagging oxygen molecules. In our experiment, nonlinear optical frequency conversion technology has been applied to generate 580nm coherent radiation.

© 1997 Optical Society of America