Experimental characterization of a self-filtering unstable resonator applied to a short pulse XeCl laser

Abstract
A self-filtering unstable resonator with magnification |M| = 5 has been applied to a pulsed UV-preionized XeCl excimer laser. In agreement with numerical results it is experimentally shown that less than two cavity round trips are needed to establish a steady state lowest-order mode. A diffraction-limited laser beam with a brightness of 1.5 × 1013 W cm−2 sr−1 has been obtained.