Development of a novel large damage site mitigation technique

Abstract

We present the development of carefully tailored shape - increased size (0.9 mm diameter) input surface mitigation sites that shadow and thus supress damage growth on the exit surface of optics. Results from downstream intensification measurements and laser induced damage experiments are presented. The results show a 6X reduction in expanding wave intensification on the exit surface of an optic, being the dominant damage onset mechanism. The tailored rounded cone design can withstand over 30 J/cm2 sub aperture input surface fluence. A significant decrease in laser induced damage initiation and growth was observed compared to shadow cones with linear profiles at input fluences higher than 10 J/cm2.