Laser-Induced Surface Engineering: Smart Surfaces and Functional Microstructures

January 25, 2026

The engineering of surface properties at the micro- and nanoscale represents a fundamental shift from traditional coating methods to the direct modification of material topology. Our research focuses on the creation of Smart Surfaces – interfaces with tailored functional responses achieved through laser-induced periodic surface structures (LIPSS) and hierarchical microstructuring. Read the article here

By utilizing femtosecond and nanosecond laser radiation, we achieve deterministic control over the physical and chemical properties of metallic surfaces.

Value of the Approach

Traditional surface finishing methods often rely on chemical treatments or additional coatings that may suffer from delamination or environmental degradation. In contrast, laser texturing modifies the substrate itself, ensuring long-term durability and structural integrity.

The primary value lies in the "programmability" of the surface: by adjusting laser parameters such as fluence, pulse duration, scanning speed, and overlap, we can induce specific functionalities including:

  • Controlled wettability (hydrophobicity/hydrophilicity).
  • Enhanced tribological performance.
  • Optimized optical absorption or scattering. Read the article here

Methodology and Laser Systems

Our methodology distinguishes between non-thermal ablation and thermal-mechanical modification:

  • Femtosecond Laser Processing: Using ultra-short pulses, we bypass the heat-affected zone (HAZ). This allows for the formation of LIPSS through the interference of incident light with surface plasmon polaritons. These are classified as High-Spatial-Frequency-LIPSS (smaller than wavelength) or Low-Spatial-Frequency-LIPSS (larger than wavelength).
  • Nanosecond Laser Texturing: Employed for larger-scale features, creating craters and ridges that serve as lubricant retaining reservoirs or light-trapping cavities.

From Plasma Lenses to Surface Topography

A critical aspect involves understanding energy redistribution. We have modeled the influence of the "plasma lens" – a cloud of ionized ablation products forming above the target. Read the article here This plasma layer acts as a refractive medium, redistributing the beam's energy and directly influencing the uniformity and periodicity of the resulting surface structures.

Surface Microstructure Analysis

Measurement follows the ISO 25178 standard for 3D surface roughness. Rather than 2D profiles (Ra), we focus on:

  • Height distribution parameters: Sq, Ssk, Sku.
  • Hybrid parameters: Sdq, Sdr (to quantify texture complexity).

Equipment utilized includes Scanning Electron Microscopy (SEM) for morphological analysis and Energy Dispersive Spectroscopy (EDS) to monitor oxidation levels, such as TiO₂ formation on titanium membranes.

Outcomes: Performance and Functionality

The implementation of these structures yields improvements across three primary domains:

  • Tribological Behavior: Nanosecond laser texturing provides micro-dimples that act as hydrodynamic bearings. These reduce contact area in dry conditions and maintain a stable oil film in lubricated environments, leading to a significant reduction in the coefficient of friction.
  • Optical Control: Femtosecond processing creates hierarchical structures that can "blacken" metals. Read the article here This can reduce reflectance from 14% to below 2% across the visible and near-infrared spectrum by increasing the light-trapping surface area.
  • Wettability and Photoelectrochemistry: Fabrication of TiO₂ membranes with micro-pyramid arrays. Combined with Atomic Layer Deposition (ALD), these surfaces increase the active surface area, improving the efficiency of photoelectrochemical water splitting for hydrogen production.

Through the synergy of laser processing and surface analysis, industry receives a toolkit for generating surfaces that are not simple boundaries, but active components of an engineering system.