| Abstract [eng] |
This dissertation investigates the mechanisms of laser-induced damage (color change and catastrophic modes) and the corresponding laser-induced damage threshold (LIDT) in optical coatings across pulse durations from a few femtoseconds to continuous-wave. Particular focus is placed on thin metallic and dielectric coatings deposited on glass substrates. In dielectric coatings, experimental studies combine LIDT measurements with fatigue characterization and temporal absorptance analysis, enabling identification of scaling laws that govern damage evolution on realistic timescales. The results demonstrate that the LIDT of color change damage follows distinct scaling behavior, and its fatigue and absorption analysis allow the establishment of an absorbed dose threshold as the governing criterion for long-term optical degradation. For metallic coatings, LIDT scaling with pulse duration is shown to be controlled by heat dissipation within the coating and substrate. Comparative assessment of predictive models reveals that classical descriptions overestimate temporal absorptance dependence, while refined models incorporating intermediate defect states yield improved agreement with experimental data. The findings provide new insights into color change fatigue mechanisms, introduce a phenomenological predictive model for the optical lifetime of dielectric coatings, and deliver practical guidelines for the design of durable coatings for ultrafast and high-average-power laser applications. |
