Role of absorbed dose in a lifetime of HfO₂ and SiO₂ dielectric coatings

This study investigates laser-induced fatigue in HfO₂ and SiO₂ dielectric coatings on fused silica using S(10⁷)-on-1 laser-induced damage threshold testing and photothermal common-path interferometry across 1030 - 257 nm wavelengths with picosecond pulses. Results show that the absorbed dose required for non-catastrophic damage, such as color change, is nearly constant across wavelengths for a fixed pulse duration and pulse count, decreasing with higher laser intensity. Thermal and laser annealing improves coating lifetimes by reducing absorptance. A proposed phenomenological model links absorption mechanisms to coating lifetime, providing insights into fatigue behavior and enabling non-destructive durability assessments for optical components under intense laser exposure.