High-power gas-discharge excimer ArF, KrCl, KrF, and XeCl lasers on buffer-gas free gas mixtures

Results of experimental studies of the gas mixture (laser active medium) effect on the lasing energy and overall efficiency of excimer discharge ArF (193 nm), KrCl (222 nm) KrF (248 nm), and XeCl (308 nm) lasers operating in buffer-free gas mixtures are presented. The optimal (in terms of maximum radiation energy) ratios of the gas components of the excimer laser active media are found, at which efficient operation is achieved with a sufficiently high power of the laser radiation. It is confirmed experimentally that for the rare gas halide discharge pumped excimer lasers the presence of a buffer gas in the active medium is not required for efficient laser operation. For example, in two-component excimer laser gas mixtures, containing working rare and halogen-containing gases, laser pulse energy of up to 170 mJ and high pulsed power of laser radiation of up to 24 MW have been attained for the first time for pulsed gas-discharge excimer lasers operating on electronic transitions at excimer ArF*, KrCl*, KrF*, and XeCl* molecules pumped by a transverse electric volume discharge of a low-pressure buffer-free gas mixture. A overall efficiency maximum of up to 0.8% was experimentally attained for binary gas mixture of KrF and XeCl lasers.