High-speed manufacturing of highly regular femtosecond laser-induced periodic surface structures: physical origin of regularity

Abstract

Highly regular laser-induced periodic surface structures (HR-LIPSS) have been fabricated on surfaces of Mo, steel alloy and Ti at a record processing speed on large areas and with a record regularity in the obtained sub-wavelength structures. The physical mechanisms governing LIPSS regularity are identified and linked with the decay length (i.e. the mean free path) of the excited surface electromagnetic waves (SEWs). The dispersion of the LIPSS orientation angle well correlates with the SEWs decay length: the shorter this length, the more regular are the LIPSS. A material dependent criterion for obtaining HR-LIPSS is proposed for a large variety of metallic materials. It has been found that decreasing the spot size close to the SEW decay length is a key for covering several cm2 of material surface by HR-LIPSS in a few seconds. Theoretical predictions suggest that reducing the laser wavelength can provide the possibility of HR-LIPSS production on principally any metal. This new achievement in the unprecedented level of control over the laser-induced periodic structure formation makes this laser-writing technology to be flexible, robust and, hence, highly competitive for advanced industrial applications based on surface nanostructuring.

LIPSS on thin metallic films: New insights from multiplicity of laser-excited electromagnetic modes and efficiency of metal oxidation

“…The fact that the modification track becomes narrower with the scanning velocity counts in favor of the proposed mechanism. Note that the width of the modification track at the largest scanning velocity 19 coincides with the diameter of the zones 1 observed at slower scanning (compare images in Fig. 8, right).…”

Surface Plasmon Polaritons on Rough Metal Surfaces: Role in the Formation of Laser-Induced Periodic Surface Structures

“…Despite the importance of , there are surprisingly few works on systematic studies of this parameter, and these works are limited to a very narrow selection of materials. 2,[22][23][24][25] For the specific case of metals, the wave propagating at the surface that contributes to ripple formation is generally identified as a surface plasmon polariton [26][27][28][29] coupled in from the incident light with help from a non-negligible surface roughness. The role of surface roughness is thus to impart momentum to the incident wave, bridging the momentum mismatch between the parallel component of the wavevector of such incident wave with that of the SPP, which lies beyond the light cone.…”

Surface‐enhanced Raman scattering studies of gold‐coated ripple‐like nanostructures on iron substrate achieved by femtosecond laser irradiation in water

“…Gnilitskyi et al investigated the formation of highly regular LIPSS on various metals (Al, Ti, Cu, Mo, Au, and steel) by changing the laser parameter (laser pulse fluences, scanning parameter, etc.) in ambient air . They achieved the regular LIPSS only on Ti, Mo, and steel among the others (Al, Cu, and Au), which might be due to the need of specific laser processing conditions (laser wavelength, scanning conditions, etc.)…”