Nanoscale boiling during single-shot femtosecond laser ablation of thin gold films

Abstract

A nanoscale chaotic relief structure appears as a result of subthreshold single-shot femtosecond laser ablation of gold films in the regimes of fabrication of microbumps and nanospikes, but only for a relatively thick film. The observed nanoablation tendency versus film thickness makes it possible to suppose the existence of a sub-surface temperature maximum in thicker gold films and its absence within thinner film, which results from competing evaporative cooling and electronic heat conduction, as demonstrated by numerical simulations of the thermal dynamics.