Due to its high corrosion resistance and mechanical properties, stainless steel is commonly used in various industrial applications, such as medical and food industries. The different types of stainless steel are chemically similar but differ in the thermal diffusivity. This factor is crucial for the laser-material interaction and, thus, laser processing in general. Therefore, this study compares the ablation threshold of three different types of stainless steel based on the method of Liu.

The samples of the three materials AISI 304, AISI 420 and AISI 316Ti were irradiated with single ultrashort pulses from different pulse widths. Thereby, the pulse duration was varied between 250 fs and 10 ps with a different set of burst modii in the GHz range. The goal is to investigate the differences in the ablation threshold and the ablation rate to improve the laser ablation efficiency. Furthermore,

the morphology and the ablated volume were evaluated by confocal microscopy.

The results show that shorter pulse durations lead to a more efficient ablation process. Furthermore, the GHz-bursts are in general less efficient in respect to ablation efficiency of a single pulse. In addition, there is a significant difference in the morphology of the pulse. Next to the ablated surface, laser-induced periodic surface structures (LIPSS) are generated. The LIPSS-structure of the shorter pulse is more extended than in the picosecond range