Efficient XeCl laser with a semiconductor opening switch in a pump oscillator: Theory and experiment

The parameters of laser radiation and kinetic processes of plasma formation and production of inverse population are studied. Electrophysical processes proceeding in a feed circuit containing a semiconductor opening switch and intermediate inductive energy storage are also considered. It is shown that the semiconductor opening switch controls the amount of energy in the inductive storage, and a high-voltage short prepulse with a peak pump power density of ~1 MW cm^-3 appearing during the current interruption can produce a volume-discharge plasma and create the inverse population for the time ~10 ns, providing the conditions for efficient pumping of the active medium from the main capacitor. The time dependences of the pump and emission powers, the concentrations of electrons, excited xenon atoms, HCl(v) molecules in excited vibrational states and of the ionisation, recombination, and attachment rates are calculated. Kinetic processes determining the parameters of laser radiation are analysed. The output energy up to 1.0 J is obtained for 90-ns (FWHM) pulses with the efficiency up to 4.0% with respect to the pump energy. The maximum output power was 11 MW for the lasing efficiency of 4.7% with respect to the pump power. The calculated and experimental time dependences of the voltage across the laser gap, discharge current, and output power are in good agreement.