Wide-aperture electric-discharge XeCl laser with ultraviolet preionization and 20-J output energy

The results are given of an investigation of the possibility of increasing the aperture of electric-discharge excimer lasers by utilizing ultraviolet preionization. It was established that the inhomogeneity of the distribution of the laser output energy over the aperture, associated with the absorption of the ultraviolet radiation, is reduced when the power of the preionization source is raised. A wide-aperture (13×10 cm) electric-discharge XeCl laser with ultraviolet preionization of an active volume of ~8.5 liters and with a 20-J output energy was constructed. The lasing was quenched because of an increase in the rate of development of a multistage ionization instability under the influence of electron–electron collisions, even when the process was partly stabilized by strong electron attachment to vibrationally excited HCl(v) molecules which was also responsible for the oscillatory nature of the development of inhomogeneities at the beginning of a discharge pulse.