Abstract

Coherent Raman spectroscopies were proposed by She et al.,¹ in 1980 as a nonintrusive and direct method for measuring high-speed molecular flows- Shortly, thereafter, subsonic speed measurements In a N₂ flow using stimulated Raman gain spectroscopy (SRGS) were demonstrated by Herring et al.² At the same time, Gustafson et al.³ used coherent anti-Stokes Raman spectroscopy (CARS) to measure flow velocity in a supersonic CH₄ jet. Although N₂ is a much weaker Raman scatterer than CH₄, experiments with N₂ are of particular interest due to the direct applicability to measurements in wind tunnels.

© 1983 Optical Society of America