Comparison of ablation rate on stainless steel using pulsed lasers in different burst modes

In this study, the ablation efficiency of single ultra-short laser pulses having different burst modes was evaluated on three types of stainless steel (AISI 420, AISI 304, and AISI 316Ti). The experiments are performed using an infrared ultra-short pulsed laser (1032 nm, 250 fs). The investigation focused on analyzing the morphology of the ablated craters to elucidate the influence of burst mode on surface quality. Additionally, the ablated volume is quantified to assess the achievable removal rate. The results indicate that the burst mode significantly affects both surface morphology of the ablated areas and the ablation volume. Moreover, the temporal pulse-to-pulse distance tp at GHz burst with tp = 450 ps and MHz burst with tp = 17 ns revealed a notable influence. By using MHz burst mode, the ablation volume for a single pulse was almost doubled compared to a pulse without burst, using the same pulse energy (from ∼ 100 µm3 to ∼ 200 µm3 depending on the steel alloy). Interestingly, by using GHz burst and bi burst the effective ablation volume drops significantly.