Two-dimensional multispecies imaging of a supersonic nozzle flow

Raman imaging is shown to be a very suitable technique for simultaneous den sity mapping of different species in dry air and N-2 supersonic nozzle flow s. The salient features of Raman scattering are its molecular sensitivity a nd 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 Opt ical Society of America OCIS codes: 290.5860, 290.5870, 300.6450, 280.2490.