Influence of the pre-pulse plasma electron density on the performance of elemental copper vapour lasers

A detailed computer model for the kinetics in an elemental copper vapour la ser (Cu-Ne-H-2) has been used to investigate the importance of the pre-puls e electron density on the performance and lasing characteristics of such a device. The results show that the laser output power and operating efficien cy are increased by 65% and 100%, respectively, at a pulse repetition frequ ency of 17 kHz, if the pre-pulse electron density is reduced by a factor of 5-10. Modelling of the plasma kinetics during the afterglow period suggest s that such a reduction is brought about when trace quantities (similar to 0.3%) of HCl are introduced into the plasma to increase the electron densit y decay rates via dissociative attachment reactions. The predicted improvem ents in laser performance which occur as a result of a reduced pre-pulse el ectron density are consistent with the observed operating characteristics o f Kinetically Enhanced copper vapour lasers which use HCl-H-2-Ne buffer gas mixtures. (C) 1998 Elsevier Science B.V. All rights reserved.