Temporally shaped femtosecond laser pulse control of two basic heat transportation processes in metals, i.e., electron-phonon coupling and electronic heat diffusion is investigated experimentally and theoretically. It is revealed that the transformation of single-pulse irradiation into double-pulse irradiation, or an adjustment of pulse-separation for double-pulse irradiation, in all case keeping the energy constant, can exert very different influence on electron-phonon coupling and electronic heat diffusion for different metals. This can lead to an unusual ablation/damage effect for nickel, i.e., an ablation/damage enhancement after double-pulse irradiation with respect to single-pulse irradiation, in comparison with the ablation/damage suppression for various other metals as widely reported. We conclude that control of heat transportation processes with tailored femtosecond pulses is suitable for robust manipulation of metal excitation and thus control of the initial steps of laser processing of metallic materials.

Date Published: 24 October 2017
PDF: 7 pages
Proc. SPIE 10457, AOPC 2017: Laser Components, Systems, and Applications, 104572W (24 October 2017); doi: 10.1117/12.2284956

Published in SPIE Proceedings Vol. 10457:
AOPC 2017: Laser Components, Systems, and Applications
Shibin Jiang; Lijun Wang; Lan Jiang; Long Zhang, Editor(s)