A long pulse discharge excited ArF laser

摘要

An X-ray preionised, discharge excited ArF excimer laser,nΛ=193 nm, has been studied in the long pulse regime. The lasernperformance is found to be primarily dependent on the dischargenstability, and therefore, on the gas composition, preionization timingnand the pumping power. Using X-ray preionization and prepulse-mainpulsenexcitation, laser pulselengths of up to 120-ns full-width atnhalf-maximum at 4 mJ/l are obtained by decreasing the partial pressuresnof the active ingredients, F2 and Ar, and using Ne as anbuffer gas. This is almost six times as long as usual for dischargenexcited ArF lasers