Toward application of hierarchical structures by ultrashort pulsed laser ablation

Abstract

Surface structuring is a versatile tool to modify the physical interplay at the interface to gaseous or liquid media. The two industrial used approaches are, in general, a chemical modification via coating or/and an introduced topography. Here, the structuring is carried out with a direct technique using an ultrashort pulsed laser with infrared and green wavelengths. Two hierarchical structural units are generated at the surface on copper, aluminum, and an amorphous alloy. Structures in the micrometer regime are produced via 2.5D layered laser ablation. Laser induced periodic surface structures (LIPSSs), an inherent phenomenon of self-generated periodic features, can be utilized to generate subdiffraction limit features. LIPSSs are demonstrated in the high spatial frequency regime with a periodicity of 320 and 600 nm for green and infrared radiations, accordingly. This work concerns the use of direct laser structuring for potential applications. Specifically, a change in the optical and wetting properties is addressed. Broadband absorbing behavior and static contact angles of up to 152° are reported. Laser ablation processes and experimental routines are presented to upscale the structuring process. Production rates up to 100 mm2/h for 2.5D ablation and 0.6 m2/h for LIPSSs can be reached.

Multiscale Hierarchical Micro/Nanostructures Created by Femtosecond Laser Ablation in Liquids for Polarization-Dependent Broadband Antireflection

“…Considering the uniqueness of LSFLs/UHSFLs obtained by fs-LA, it is highly desirable to integrate them onto microstructures in order to construct multiscale hierarchical micro/nanostructures, which will promise the generation of specific functions. To date, although many hierarchical micro/nanostructures [34,35] have been created and some of them have been applied in cellular behavior control [36,37], color imprinting [38], antireflectance [35,39,40] and superhydrophobicity/superoleophobicity [41][42][43], a report on the preparation and application of LSFLs/UHSFLs-containing hierarchical micro/nanostructures is still lacking.…”

Evolution of microstructures on stainless steel induced by ultra-short pulsed laser ablation

“…This leads to limiting constraints, where high average power must be distributed on the workpiece by high scan speeds and repetition rates [21]. To date there is plenty of laser power with high repetition rates available, but depending on the necessary focal spot size the beam steering [22] or controllers [23] are constraining the maximal laser machining speed. Using the laser in a burst mode with small temporal pulse spacing can enhance the maximal applicable average power [24] and ablation rate [25][26][27].…”

Modification of Ti6Al4V surface properties by combined DLW-DLIP hierarchical micro-nano structuring

“…For the achievement of this kind of surface properties, the use of pulsed laser irradiation techniques has proven to be a clearly effective procedure, different conceptual approaches having been the subject of research and extensively reported in the literature [19][20][21][22].…”