Laser Induced Periodic Surface Structures Induced by Surface Plasmons Coupled via Roughness

TL;DR

This paper critically examines the formation mechanisms of femtosecond laser-induced periodic surface structures, challenging the common surface plasmon coupling theory and proposing hydrodynamic instabilities as an alternative explanation.

Contribution

It provides a new analysis of LIPSS formation, questioning the surface plasmon coupling theory and suggesting hydrodynamic instabilities as a more consistent mechanism.

Findings

Surface plasmon coupling theory contradicts laser-ablation experimental results.

Hydrodynamic instabilities in the melt layer offer a plausible alternative explanation.

The study advances understanding of femtosecond laser surface structuring.

Abstract

In this paper the formation mechanisms of the femtosecond laser-induced periodic surface structures (LIPSS) are discussed. One of the most frequently-used theories explains the structures by interference between the incident laser beam and surface plasmon-polariton waves. The latter is most commonly attributed to the coupling of the incident laser light to the surface roughness. We demonstrate that this excitation mechanism of surface plasmons contradicts to the results of laser-ablation experiments. As an alternative approach to the excitation of LIPSS we analyse development of hydrodynamic instabilities in the melt layer.