A method for determining material hardness of metals is based on laser-induced shockwaves generated with a pulsed TEA-CO2 nanosecond laser. The laser creates a plasma, which interacts further with the laser beam and subsequently generates a shockwave. The shockwave is ignited above a spherical indenter, made of Al2O3, which is pushed thereby into the metal surface. The indentation geometry can be analyzed to draw conclusions about material properties. The process duration depends mainly on two factors: Generating and analyzing the indentations. To speed up the indentation process an approach with a constant movement of the specimen during indentation was tested. The results indicate that velocities up to 1.8 m/min do not have a significant influence on indentation diameter and depth. Therefore, positioning times with acceleration and deceleration can be avoided and thus up to 30 indentations per second with a distance of 1 mm between each indentation could be realized.

Precise 2.5D microstructure fabrication on large areas (>1 m²) remains a challenge for industrial applications. Using a 248 nm KrF excimer laser with grayscale masks, we successfully created sub-10 µm asymmetric microstructures on polycarbonate sheets. Grayscale mask features modulated the laser fluence, enabling depth variation for 2.5D shapes. For large area substrates, a floating objective head mitigates substrate thickness variations, ensuring focus over large areas. The incubation effect was exploited to enhance material absorbance, allowing controlled microstructure formation at sub-threshold fluences. Replication into PDMS confirmed the fidelity of fabricated structures. This work demonstrates a scalable and precise fabrication method for creating sub-10 µm asymmetric microstructures, addressing critical challenges in advancing industrial applications such as functional printing, optics, and microfluidics.

It is widely accepted that the femtosecond laser damage resistance of thin films is primarily influenced by factors such as material bandgap, electric field intensity, and the structure of the thin-film stack. With all these being optimized, it is found that the thickness of overcoat plays an interesting role in this as well. Unlike a thick overcoat, a thin overcoat can noticeably reduce both the laser damage resistance and fatigue performance, even when the overcoat layer is deposited with wide bandgap material and subjected to minimal electric field intensity. This phenomenon is being investigated as a factor of thin film optimizing for ultrafast laser applications.

Glass etching using a short wavelength laser in combination with an absorbing top-coat is re-visited. We wanted to refine the process and understand the mechanism that creates shallow structures without the need of subsequent gaseous or wet etching of the glass.

A porous particulate film of 99% carbon was deposited on a 0.15mm thick glass slide. A violet wavelength multi-mode laser with micro-spot optics focused a square 10um spot on the absorbing film stack. After exposure, the remainder of carbon is removed, and smoothly etched lines in the glass are observed. AFM and optical profilometer measurements showed V-shaped trenches 4 to 5um wide, 100nm deep, with the built-up material along the grooves around 25nm in height, and a RMS roughness in the channel of 6nm. Possible applications of this cost-effective technique for life-sciences structured substrates, for micro-fluidics, or as re-distribution layers in stacking of semiconductor chips are presented.

Diamond-like carbon (DLC) coatings and laser texturing are strategies used to improve the performance of functional surfaces in a wide range of applications, such as automotive, aerospace, cutting tools, optical devices and medical implants. They have mainly been exploited independently but, recently, a new approach combining DLC coating and laser technology to further enhance performance is being explored. In this work, three different strategies to obtain nanostructured DLC coatings on polycarbonate (PC) substrates are studied. Laser-induced periodic surface structures (LIPSS) generated on the PC substrate, both those created directly by a UV source and those replicated by hot embossing from a mould, and then transferred to the DLC coating, and LIPSS induced directly on the surface of the DLC coating are compared. SEM and optical profilometry are used to analyse the generated structures, while EDS analysis is used to evaluate the chemical changes produced in the DLC coatings.

The employment of ultrashort laser pulses has enabled the fabrication of grating structures on a shape memory material, suitable for strain measurement via the interference pattern. This development signifies a novel application of laser-generated microstructures and facilitates direct strain measurement on the object without the necessity of an additional layer, as often required by conventional methods. The grating constant was varied between 5 µm and 10 µm. Furthermore, Laser Induced Periodic Surface Structures (LIPSS) has been demonstrated to function as a structure for the purpose of producing lower grating constants. The employment of LIPSS has been demonstrated to result in a grating constant reduction to approximately 620 nm. Moreover, the employment of LIPSS eliminates the requirement for monochromatic light in strain measurement applications. Illumination with a white light source leads to a color shift in the reflected light, which depends on the degree of stretching.