Laser micromachining of silicon and cemented tungsten carbide using picosecond laser pulses in burst mode: ablation mechanisms and heat accumulation

This paper presents results obtained by studying material removal of silicon and cemented tungsten carbide using high-frequency ultrashort-pulsed laser radiation. In laser-induced material removal, ablation mechanisms and heat accumulation effects are considered. Depending on the fluence and number of pulses in a burst, structures are created on silicon and cemented tungsten carbide in order to be able to determine the ablated volume. A single pulse in the burst represents the conventionally pulsed laser radiation. Depending on the number of pulses, the ablated volume per pulse rises in the burst. Furthermore, an increase in the number of pulses in the burst results in a repetitive decrease as well as an increase in the ablated volume. Investigations at different ambient pressures establish that this phenomenon could be changed for cemented tungsten carbide under fine vacuum. The simulations demonstrate that the laser-induced heat accumulation in burst mode contributes significantly to the removed volume.