Ultrafast laser induced surface modification in absence of non-thermal melting and evaporation

TL;DR

This paper investigates how femtosecond laser pulses can modify conductive surfaces through capillary effects alone, without melting or evaporation, using a hybrid model supported by simulations and experiments.

Contribution

It introduces a novel understanding of laser-induced surface structuring driven solely by capillary effects, bypassing traditional thermal melting or evaporation mechanisms.

Findings

Surface morphology changes can be achieved without non-thermal melting or evaporation.

Simulations and experiments confirm the role of capillary effects in surface modification.

Intermediate surface states lead to microcone formation.

Abstract

The present paper elucidates the physical mechanism that accounts for the principal/primary stages of the structuring process taking place upon irradiation of a conductive solid with multiple identical femtosecond laser pulses, based on the consideration of a hybrid theoretical model. Heat transfer along with hydrodynamics simulations demonstrate that it is possible to create morphology change conditions by solely exploiting capillary effects, in the absence of either non-thermal melting or evaporation. Simulation results, confirmed by experiments, reveal the intermediate surface modification stage acting as a predecessor of microcones formation.