Atmospheric pressure pulsed HF chemical laser

Experiments are described on a pulsed chemical laser operating on the reaction between hydrogen and fluorine at pressures above the second explosion limit. A laser energy density of 80 J/liter-atm is obtained for a mixture of 0.1 F2/0.1 H2/0.8 He mole fraction at 1.1 atm total pressure. This performance corresponds to a chemical efficiency of 4% and an over-all electrical efficiency of 1.3% for the particular photolysis geometry employed. Various diagnostic experiments are developed to measure the initial fraction of F2 dissociated by the photolysis, the temporal extent of the over-all reaction, and measurements of medium homogeneity. These data together with measurements of over-all laser performance are compared with calculations from a comprehensive theoretical model which includes the photolysis process, chemical kinetic reactions, vibrational energy transfer processes, and stimulated emission. The major features of this laser appear to be understood and described by the existing kinetic rate data. However, certain important effects, such as the influence of rotational nonequilibrium and optical output coupling, remain to be fully understood.