Numerical simulation and experimental validation of ultrafast laser ablation on aluminum

In this paper, a numerical study of the ultrashort single pulse ablation process in aluminum has been conducted using the two-temperature model, taking into consideration the several dependencies of the parameters on temperature. The evolution of temperatures for each point within the material over time is obtained, allowing to comprehend the distribution of energy in the laser-metal interaction and its subsequent diffusion within the material. This study allows to gain a more precise understanding of the thermophysical and optical properties throughout the material heating and ablation process. The ablation process has been experimentally validated using a femtosecond laser on a polished aluminum film for a wide range of fluences. The developed theoretical model and the experimental values are in good agreement for both ablation depth and diameter across the entire range of powers studied, enabling reliable determination of the threshold fluence, laser spot size and material absorption coefficient. These parameters are crucial for achieving optimal micromachining processes.