| Abstract: | Coherent anti-Stokes Raman scattering is demonstrated as a quantitative diagnostic in low-density flows by mapping H(2) velocity and translational temperature inside and outside the nozzle of a resistojet. A spatial resolution of better than 35 mum along the flow direction and 350 mum transverse to it was attained in a density as low as 5 x 10(15) cm(-3). The accuracy of the velocity, inferred from the Doppler shift of the Q (1) Raman resonance, was limited by the scan linearity of the laser to +/-0.2 km/s. Translational temperatures, inferred from linewidths and complicated by saturation and ac Stark effects, had an accuracy of ~20%. A discussion of applicability to molecular nitrogen is presented. |
