EXCIMER ARF LASER WITH AN OUTPUT ENERGY OF 0.5 J AND HE BUFFER GAS

An experimental investigation was made of the energy and temporal char acteristics of a gas-discharge excimer ArF laser (lambda = 193 nm) wit h gaseous mixtures containing He as the buffer gas. An RU-65 spark gap was used. The parameters of a high-voltage excitation circuit, of the LC inverter type with automatic UV preionisation, were optimised. A g aseous active mixture had the He:Ar:F-2 = 79.7:20:0.3 composition and the total pressure was 2.5 bar. An efficiency of 1.5%, relative to the stored energy, was obtained for the first time for an output radiatio n energy of 360 mJ. The maximum output energy of the ArF laser was 550 mJ; the corresponding efficiency was 1.36% and the pulse duration at half-amplitude was 12 ns.