Double- and Multi-Femtosecond Pulses Produced by Birefringent Crystals for the Generation of 2D Laser-Induced Structures on a Stainless Steel Surface

Abstract

Laser-induced textures have been proven to be excellent solutions for modifying wetting, friction, biocompatibility, and optical properties of solids. The possibility to generate 2D-submicron morphologies by laser processing has been demonstrated recently. Employing double-pulse irradiation, it is possible to control the induced structures and to fabricate novel and more complex 2D-textures. Nevertheless, double-pulse irradiation often implies the use of sophisticated setups for modifying the pulse polarization and temporal profile. Here, we show the generation of homogeneous 2D-LIPSS (laser-induced periodic surface structures) over large areas utilizing a simple array of birefringent crystals. Linearly and circularly polarized pulses were applied, and the optimum process window was defined for both. The results are compared to previous studies, which include a delay line, and the reproducibility between the two techniques is validated. As a result of a systematic study of the process parameters, the obtained morphology was found to depend both on the interplay between fluence and inter-pulse delay, as well as on the number of incident pulses. The obtained structures were characterized via SEM (scanning electron microscopy) and atomic force microscopy. We believe that our results represent a novel approach to surface structuring, primed for introduction in an industrial environment.

Laser engineering of biomimetic surfaces

“…Another promising approach is the interplay between pulse delays in double-pulse irradiation experiments. Recently, many works, have used the combination of different polarization states [259][260][261][262][263][264] or different wavelengths [265][266][267] of two consecutive time delayed ultrashort laser pulses to fabricate 2D-LIPSS structures. The double-pulse interplays in combination with crossed polarization or counter rotating circularly polarized laser pulses can produce ordered 2-dimentional surface structures for specific pulse to pulse delays.…”

“…Fig. 27 from Fraggelakis et al [265] shows the variation of surface morphologies of stainless steel after double-pulse irradiation with an inter-pulse delay ranging from 0 to 10 ps, for both polarization configurations: double cross-polarized (XP) and double circular counter rotating polarizations (CP). Finally, the combination of cylindrically polarized laser pulses with Gaussian ones on a pulse-to-pulse interplay is yet to be investigated as it can potentially lead to promising possibilities of complex bio-inspired surface structures.…”

Review on Experimental and Theoretical Investigations of Ultra-Short Pulsed Laser Ablation of Metals with Burst Pulses

“…For a fixed total fluence of the burst of 0.25 J/cm 2 , the formation of HSFL is enhanced by using three or four pulses in the burst, as the fluence of each pulse in the burst becomes smaller. Increasing the total fluence will lead to microgrooves, nanoholes, and melt formations in the central region of the machined grooves, sometimes referred to as “micro-hills” [ 194 ].…”

Self-Organization Regimes Induced by Ultrafast Laser on Surfaces in the Tens of Nanometer Scales

“…The control of the ultrafast laser pulse polarization, inter-pulse delay and laser fluence leads to the generation of innovative 2D surface morphologies on different scales. Several works focused on the fabrication of 2D-LIPSS in the nearsubmicron length [15][16][17]. These microstructures can lead to strong modifications on surface wetting [18], tribological and optical properties [19].…”