Articolo in rivista, 2014, ENG, 10.1364/OE.22.012200

Role of heat accumulation on the incubation effect in multi-shot laser ablation of stainless steel at high repetition rates

Di Niso, Francesca; Gaudiuso, Caterina; Sibillano, Teresa; Mezzapesa, Francesco Paolo; Ancona, Antonio; Lugara, Pietro Mario

Istituto di Fotonica e Nanotecnologie (IFN)-CNR U.O.S. Bari, via Amendola 173, I-70126 Bari, Italy Università degli Studi di Bari, Dipartimento Interuniversitario di Fisica, via Amendola 173, I-70126 Bari, Italy

We study the incubation effect during laser ablation of stainless steel with ultrashort pulses to boost the material removal efficiency at high repetition rates. The multi-shot ablation threshold fluence has been estimated for two pulse durations, 650-fs and 10-ps, in a range of repetition rates from 50kHz to 1 MHz. Our results show that the threshold fluence decreases with the number of laser pulses N due to damage accumulation mechanisms, as expected. Moreover, approaching the MHz regime, the onset of heat accumulation enhances the incubation effect, which is in turn lower for shorter pulses at repetition rates below 600 kHz. A saturation of the threshold fluence value is shown to occur for a significantly high number of pulses, and well fitted by a modified incubation model. (C) 2014 Optical Society of America

Optics express 22 (10), pp. 12200–12210

Keywords

Ultrafast lasers, Laser damage, Laser materials processing, Thermal effects, Ultrafast processes in condensed matter including semiconductors

CNR authors

Mezzapesa Francesco Paolo, Lugara Pietro Mario, Di Niso Francesca, Gaudiuso Caterina, Sibillano Teresa, Ancona Antonio

CNR institutes

IFN – IFN - Sede secondaria di Bari