Defect formation in oxide thin films

Abstract

In nanosecond laser damage investigations, the specific defect density in the optical component or thin film plays the key role in triggering optical breakdown. UV irradiation can induce additional defects in optical materials before the damaging event takes place. This increased defect density can even be the main cause for UV laser damage as shown before in fused silica. Moving on to oxide thin films, this contribution will present studies on SiO 2 , Al 2 O 3 , and HfO 2 ion beam sputtered coatings. Pure material single layers as well as composite material single layers comprised of two oxides have been investigated concerning their tendency to generate additional defects resulting from UV laser irradiation. Within this work, tests at 355 nm and 266 nm have been performed and are compared.