Excimer ArF laser with an output energy of 0.5 J and He buffer gas

Abstract

An experimental investigation was made of the energy and temporal characteristics of a gas-discharge excimer ArF laser (λ =193 nm) with 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 gaseous active mixture had the He : Ar : F2 = 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 radiation 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 12ns.