Research on the metal ablation thresholds of picosecond laser

Detailed studies on the ablation threshold of Mo with picosecond laser pulses are reported in this paper. The laser pulses used for the research were 1064 nm in wave length and 15 ps in pulse duration. Scanning electronic microscope (SEM) and optical surface analyzer were used to analyze the ablation sample, and by analyzing the linear relationship between the squared diameter of ablation crater and pulses energy we obtained the ablation threshold of Mo with single- and multi-pulses. Influence factors of ablation threshold were observed while analyzing machining process. Finally, the shape and topography of holes drilled by percussion with ablation regularity in Mo were studied, which provided an important guidance for the following applications on picosecond micro-machining.