Excimer laser with highly coherent radiation

Experimental studies aimed at the optimisation of an unstable resonator of an ArF electric-discharge laser are performed. Several optical schemes of an unstable resonator of a single-module laser are proposed and investigated. It is shown that the laser developed on the basis of these schemes is characterised by a high coherence (the spatial coherence length is 1 – 10 mm and the temporal coherence length is 0.5 – 30 mm at a pulse energy of 40 – 290 mJ).