Ultrashort pulsed laser ablation of stainless steel with MHz bursts

This study investigates the ablation process of stainless steels using ultrashort pulsed laser bursts with a MHz intra-burst repetition rate. Multiple laser parameters, including pulse fluence, pulse number per burst, inter-burst repetition rate and scan speed, are varied to study their influences on the ablation process. Laser ablation in single-pulse and burst modes are compared in terms of ablation efficiency and surface quality. It is found that burst-mode ablation can generate much better surface quality than single-pulse ablation, despite slightly reduced ablation efficiency. Different types of surface structures can be generated by the ablation process and their formation mechanisms are analyzed. This work highlights the advantage of burst-mode ablation in achieving ultra-smooth surfaces on stainless steel and unveils the optimization strategy for machining high-quality microstructures while maintaining high ablation efficiency.