Ten Open Questions about Laser-Induced Periodic Surface Structures

Abstract

Laser-induced periodic surface structures (LIPSS) are a simple and robust route for the nanostructuring of solids that can create various surface functionalities featuring applications in optics, medicine, tribology, energy technologies, etc. While the current laser technologies already allow surface processing rates at the level of m2/min, industrial applications of LIPSS are sometimes hampered by the complex interplay between the nanoscale surface topography and the specific surface chemistry, as well as by limitations in controlling the processing of LIPSS and in the long-term stability of the created surface functions. This Perspective article aims to identify some open questions about LIPSS, discusses the pending technological limitations, and sketches the current state of theoretical modelling. Hereby, we intend to stimulate further research and developments in the field of LIPSS for overcoming these limitations and for supporting the transfer of the LIPSS technology into industry.

Direct Laser Writing of Copper Micropatterns from Deep Eutectic Solvents Using Pulsed near-IR Radiation

“…The laser-induced periodic surface structure’s (LIPSSs) formation on the deposited copper layer was observed ( Figure 4 ) in some of the processing regimes, at a scanning speed of 0.05 mm/s and a laser power of 1.3–3.1 W. LIPSSs are a commonly known phenomena, resulting from the regular polarization and wavelength-dependent patterns on the laser-treated surfaces (including copper [ 57 , 58 ]). Although LIPSSs have been extensively studied over the last few decades [ 48 , 59 ], to the best of our knowledge, this is the first report of LIPSS formation in the conditions under consideration. Nevertheless, the common model is applicable to explain LIPSS formation during the process of laser-induced deposition, using DES.…”

LIPSS Applied to Wide Bandgap Semiconductors and Dielectrics: Assessment and Future Perspectives

“…For dielectrics, such as fused silica, supra-wavelength periodic surface structures following melting and subsequent capillary and reorganizing effects have been observed after the incidence of ultrashort laser pulses [52]. To deal with the main and general outlines and open questions about LIPSS for such materials, it is suggested to refer to a recent explicative perspective paper by Bonse and Gräf [53].…”

Formation of Nano- and Micro-Scale Surface Features Induced by Long-Range Femtosecond Filament Laser Ablation

“…Two types of ripple are distinguished in the literature, according to in their characteristic spatial period: (I) LSFL ripples, denoting l ow- s patial- f requency L IPSS with a period near the wavelength of the irradiating laser beam, and (II) HSFL ripples, denoting h igh- s patial- f requency L IPSS as a kind of periodic nano structure with a period considerably smaller than the laser wavelength. In a very recent publication asking ten open questions about LIPSS [ 7 ], it was made apparent that the formation mechanism of ripple structures is still a topic of scientific discussion. Different theories were presented in the past, including self-organization effects, optical interference, and the scattering of the incident radiation at surface defects, surface plasmon polariton excitation, and hydrodynamic processes [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ].…”

“…In a very recent publication asking ten open questions about LIPSS [ 7 ], it was made apparent that the formation mechanism of ripple structures is still a topic of scientific discussion. Different theories were presented in the past, including self-organization effects, optical interference, and the scattering of the incident radiation at surface defects, surface plasmon polariton excitation, and hydrodynamic processes [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. All these complex physical processes affect the coupling efficiency of incident laser radiation, which may result in periodic energy distribution and modulated material removal to finally form periodic surface reliefs.…”