Aerothermodynamic and Thermal Phenomena in a High Pulse-Repetition Rate XeCl Laser

Abstract

Previous studies (Borisov et al. 1987; Sentis et al. 1989; Canarelli 1989) have shown that for high pulse repetition rate XeCl lasers (≥ 300 Hz for an energy deposition of ~ 50 J/l.b), the laser average power generally decreases. This decrease is mainly due to density fluctuations in the active medium, electrode material, composition of the gas mixture, flow characteristics, dust contamination level, preionization level, etc. (Baranov et al. 1984; Taylor 1986). In this paper, a new approach of the study of acoustic phenomena shows that one of the main processes of shock wave production is related to current over-densities and electric arcs occurring during the energy deposition in the laser gas mixture. A theoretical study of electrode temperature increase is also developed. It shows that thermal phenomena (electrode heating) leads to a drop of the output laser energy.