Abstract

Since the first report, nonintrusive techniques for measuring fluid flows using lasers have undergone nearly two decades of research, development, and applications. Most laser techniques which depend on Mie scattering of particles are, however, limited by the problem of particle lag and spectroscopic methods which probe the motion of atoms or molecules directly are more desirable. In the past few years, two popular spectroscopic techniques which measure the Doppler shift due to moving atoms or molecules have been used for this purpose. These methods are laser-induced fluorescence and coherent Raman spectroscopy. Successful velocity measurements in both supersonic and subsonic flows have been made with both fluorescence¹ and Raman techniques.²

© 1984 Optical Society of America