A 300-J Multigigawatt CO2 Laser

Abstract

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 cm2 in 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 CO2 gas mixtures are obtainedwith 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. Show more