Influence of pulse duration and separation on ultrafast single pulse laser ablation in industrial bulk metals: Complete time-resolved surface dynamics and its implications to laser material processing (Conference Presentation)

The pulse duration dependence and inter pulse separation of pulse sequences influence on the energy specific ablation volume are still today open questions in laser material processing. The complete timescales for the processes involved in laser ablation can be visualized from the initial pulse absorption to the material removal occurring on a microsecond time scale by using an pump-probe microscopy method. Here we present time-resolved and energetic studies of the surface dynamics of the laser ablation processes on aluminium, copper and stainless steel bulk materials, which were analysed for pulse durations ranging from 500 fs to 20 ps, while keeping all other laser parameters constant. Our results indicate that the ablation process should be initiated by pulse durations shorter than the mechanical relaxation time of 3 ps and remain uninterrupted until the final state is reached after about 1 µs.