Raman imaging is shown to be a very suitable technique for simultaneous density mapping of different species in dry air and N2 supersonic nozzle flows. The salient features of Raman scattering are its molecular sensitivity and the fact that it can be spectrally separated from strong reflections and Mie scattering. We collected Raman images of both N2 and O2 concurrently by imaging the flow through an imaging spectrograph with a broad entrance slit onto a CCD camera. The main advantage of this method is that different species can be imaged under exactly the same flow conditions.
© 1999 Optical Society of America
N. M. Sijtsema, R. A. L. Tolboom, N. J. Dam, and J. J. ter Meulen, "Two-dimensional multispecies imaging of a supersonic nozzle flow," Opt. Lett. 24, 664-666 (1999)