Metal micromachining with shaped femtosecond laser pulses

This paper studies the ablation of aluminum foil (50 μm thickness) under various conditions by observing the morphology of ablation caves and by analyzing the relationship of the photodiode signal of transmitted light and the number of pulses to penetration. In order to obtain better condition of ablation, several variable quantities in the experiment are tested, which are the pulse energy, position of laser focus relative to sample surface, ambient pressure and pulse shape. Preferable results are obtained by using some specific shaped pulses to ablate samples, compared to those obtained with transform-limited pulses, which means laser pulse shaping technology can be of important usage and application in micromachining metal material. (authors)