Two-dimensional multispecies imaging of a supersonic nozzle flow

Raman imaging is shown to be a very suitable technique for simultaneous density mapping of different species in dry air and N-2 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 N-2 and O-2 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. (C) 1999 Optical Society of America OCIS codes: 290.5860, 290.5870, 300.6450, 280.2490.