Ultrafast modulation of the molten metal surface tension under femtosecond laser irradiation

TL;DR

This paper predicts that femtosecond laser pulses can rapidly modulate the surface tension of molten metals by inducing anisotropic stress relaxations within picoseconds, enabling ultrafast control of liquid surface behaviors.

Contribution

It introduces a novel mechanism for ultrafast modulation of liquid surface stress fields using femtosecond laser irradiation, supported by two-temperature model molecular dynamics simulations.

Findings

Surface tension modulated sharply within picoseconds after laser pulse.

Development of nanometer scale non-hydrostatic regime behind liquid surface.

Potential for ultrafast manipulation of liquid surface transport and patterning.

Abstract

We predict ultrafast modulation of the pure molten metal surface stress fields under the irradiation of the single femtosecond laser pulse through the two-temperature model molecular-dynamics simulations. High-resolution and precision calculations are used to resolve the ultrafast laser-induced anisotropic relaxations of the pressure components on the time-scale comparable to the intrinsic liquid density relaxation time. The magnitudes of the dynamic surface tensions are found being modulated sharply within picoseconds after the irradiation, due to the development of the nanometer scale non-hydrostatic regime behind the exterior atomic layer of the liquid surfaces. The reported novel regulation mechanism of the liquid surface stress field and the dynamic surface tension hints at levitating the manipulation of liquid surfaces, such as ultrafast steering the surface directional transport and patterning.