Optimization of the pre-pumping NO/ClO2 chemistry in a purely chemical HCl laser

The laser output at 3.8 micrometers from a purely chemical HCl laser was used to obtain information about the pre-pumping chemistry of the NO/ClO2 system. The reaction of chemically produced chlorine atoms with hydrogen iodide was the laser pumping reaction. Successful laser operation was confirmed using three different kinetic or chemical modes. These modes are distinguishable by whether the chlorine enters the optical (laser) region directly in the form of chlorine atoms, ClO radicals or parent ClO2 molecules. A comparison of experimental results for the latter two modes, using computer simulation results for the time evolution HCl, showed that the main features of the coupling of the pumping reaction to the pre-pumping chemistry are understood. (Author)