Damage performance of alumina ceramic by femtosecond laser induced air filamentation

Hard and brittle materials, such as ceramics, are extensively utilized in defense and military protection. Studies on laser damage to ceramic materials have garnered significant attention, with a focus on efficient disruption over long-range. The femtosecond laser filamentation allows energy transfer on the order of kilometers, providing a unique advantage for applications requiring long-distance destruction. However, the interaction mechanism between femtosecond laser filamentation with hard and brittle materials remains unclear. This study initially simulates the interaction of femtosecond lasers with alumina ceramics at various pulse energies using the two-temperature equation. The results reveal the variation in electron and lattice temperature under the irradiation of femtosecond laser. Subsequently, the damage performance caused by femtosecond laser filamentation on ceramic materials, considering various pulse energies, filament positions, and ablation times are systematically investigated. Additionally, at a pulse energy of 4 mJ, the filament length focused by a 500 mm lens can extend up to 25 mm, resulting in an ablation hole with a diameter of 340 µm and a depth of 440 µm along the middle part of the filament. The power-clamping effect ensures uniform damage hole morphology and size across the entire filament, attributable to the constant filament diameter and plasma intensity. This elucidates the damage mechanism of filaments and adequately validates the effectiveness of this method, establishing a theoretical foundation for investigating laser remote damage of hard and brittle materials.