CO2 vibrational temperature measurements in CO + N2O gasdynamic laser

A method for measuring vibrational temperatures of the CO2 asymmetric mode T3 and symmetric modes T2 under CO2 gasdynamic laser cavity conditions is described. The method is based on the simultaneous recording of IR emission intensity in the CO2 asymmetric stretch band at 4.3 microns and gain for 10.6 microns in the CO2 laser transition, while theoretical models are used to determine vibration-rotation bands. Vibrational temperatures were determined for CO2-N2O reaction products in a shock tube nozzle flow for different gas conditions behind the reflected shock wave. A comparative study of gain and vibrational temperature was performed for a reacting CO-N2O-He mixture and for an equivalent inert CO2-CO-N2-He mixture, consisting of final reaction products.