A 300-J multigigawatt CO2laser

The development of a new transverse electric discharge scheme has permitted the excitation of large volumes of CO2, N2, and He mixtures with beam cross sections up to 60 cm²in area. The scheme utilizes as a preionizer a sheet of small arc discharges produced prior to the main discharge and situated behind a perforated anode. Time-resolved photography establishes that rapid volumetric ionization of the gas between the electrodes occurs concurrent with the formation of these arcs. This behavior is consistent with a preionization mechanism depending upon UV photo-excitation of the gas. A parametric study has shown that reproducible discharge conditions in 30 percent CO2gas mixtures are obtained with input energies of >300 J.I^-1, resulting in energy extraction efficiencies of ∼10 percent and an average small-signal gain of ∼4.3 percent cm^-1. The laser is modular in construction and, when a number of discharge modules are employed in series in a simple oscillator configuration, energies of ∼300 J with peak powers of several gigawatts are obtained.