Using rotational raman scattering to study gas impurities

The use of optical diagnostic methods (spontaneous Raman scattering and coherent anti-Stokes light scattering) to measure gas impurity concentrations of less than 0.1% is studied. The shapes of measured and calculated rotational Raman scattering spectra were compared to process experimental data. The technique was tested for measuring nitrogen, oxygen, and hydrogen concentrations in jets. Under the conditions of these experiments, changes in the ratio of oxygen and nitrogen concentrations during air diffusion into helium and hydrogen were not observed.