Pulsed 500-J CO2 laser

The paper reports on a CO2 laser with 10 liter active medium volume, 500-joule pulse, and conversion efficiency of 33%, in which preionization of the working medium is accomplished by a 200-keV electron pulse with pulsed current up to 1.5 kA and pulse duration from .5 to 1.5 microseconds. The laser consists of an electron gun and a laser cell filled with a 1:1:3 CO2-N2-He mixture at atmospheric pressure. Energy for exciting the active volume is stored in a battery of low-induction condensers. During discharge, the initial and residual voltages are measured in order to determine the pumping energy. An expression is given for calculating the pumping energy in terms of condenser battery capacitance, distance between cathode and anode, electric field strength, gas volume, recombination coefficient, electron pulse duration and density, ionization cross section, gas pressure, and particle number density. Greatest efficiency of 33% was obtained in a field of 5.5 kV/cm.