EXCIMER KRP LASER WITH HE BUFFER GAS, 0.8 J ENERGY, AND 2-PERCENT EFFICIENCY

An experimental investigation was made of the energy and temporal char acteristics of the pump process and of the output radiation of a pulse d gas-discharge excimer KrF laser (lambda = 248 nm) with He as the buf fer gas. An RU-65 spark gap was used as the design base. The parameter s of a high-voltage excitation circuit of the LC inverter type with au tomatic UV preionisation were optimised, A laser efficiency (based on the stored energy) of 2.4% and an output radiation energy of 0.57 J we re reached for the first time for a gaseous medium of the He:Kr:F-2 = 89.8:10:0.2 composition at a total pressure of 2.5 bar. The maximum ou tput energy of the KrF laser was 0.82 J in the form of pulses of 24 ns duration at half-amplitude; the specific output energy was then 5.9 J litre(-1) and the efficiency was 2.0%.