Output beam focusability of a Nd:glass zig-zag slab laser

The focusability of a zig-zag optical path laser with a 230*65*5 mm Nd:glass for application to soft X-ray generation is described. A Q-switched laser output energy of 18.3 J with a pulse width of 28 ns was obtained in a phosphate glass LHG-5 (Nd:8 wt.%), with an extraction efficiency of 71% from a stored energy of 26 J at a pumping energy of 4 kJ. The focusability was achieved up to 6.2*10/sup 12/ W/cm/sup 2/ in a spot size of 100 mu m, which was sufficient intensity to generate soft X-rays for X-ray lithography.>