Real-time in-situ measurement of the penetration depth in short pulse laser percussion drilling of metal targets

In this work, direct investigations of short pulse laser micromachining have been carried out by implementing a contactless sensor based on laser diode self-mixing feedback interferometer. Laser percussion drilling experiments have been performed in air using a 120 ps microchip fiber laser amplifier. The laser self-mixing sensor allowed to follow in real-time the displacement of the ablation front, thus simultaneously monitoring the material removal rate with submicrometric resolution, in different sample materials and varying the working parameters.