Ultrashort pulse laser ablation of dielectrics: Bridging the “bandgap” from free electron generation to hydrodynamic ablation

Abstract

This paper presents an extension to a general-purpose hydrodynamic simulation model [Zenz et al., Comput. Fluids 268, 106109 (2024); Florian et al., Procedia CIRP 124, 602 (2024)] for laser-based processes, enabling the simulation of ultrashort pulse laser ablation of dielectric materials. The model incorporates free electron generation through multiphoton and avalanche ionization, charge carrier recombination, as well as their advection. These processes are fully coupled with compressible multiphase hydrodynamic equations, allowing for the investigation of phenomena typically unobservable experimentally. A comprehensive validation against experimental data assesses the model’s accuracy across various laser fluences. Additionally, the effects of different laser fluences on the absorption and ablation dynamics, as well as the material removal efficiency are explored. This extended model offers a powerful tool for understanding and optimizing ultrashort pulse laser ablation of dielectric materials.