Study on the effect of size and density of micropores on transparent ceramic damage induced under intense laser irradiation

The increasing utilization of transparent ceramics in laser systems, particularly the magnesium aluminate spinel (MgAl2O4) transparent ceramic, has positioned it as the primary candidate for high energy laser system exit windows. Nevertheless, the increased energy and power of laser output necessitate higher standards for the laser-induced damage threshold in transparent ceramics. Residual micropores within transparent ceramics pose a potential source of damage. In this study, we employed the post-annealing process to effectively modulate the density and size of micropores. We first established the relationship between the density and size of micropores and laser damage threshold, which described the damage morphology of transparent ceramic in detail. Subsequently, we developed a multi-physical field coupled kinetic model of laser damage in micropores, providing a quantitative analysis of how factors such as micropore size and density influence the damage morphology of transparent ceramic surfaces when subjected to laser irradiation. Using time-resolved pumping and probing technology, we conducted in situ detection of laser damage caused by micropores, enabling detailed examination of damage kinetic behavior. Ultimately, this study elucidated the physical mechanism behind micropore-induced transparent ceramic damage. This has significant implications for enhancing the anti-laser damage performance of transparent ceramics in high-intensity laser systems.