Lasers and Photonics for Advanced Manufacturing II

We have developed a simple and versatile configuration for direct laser interference patterning of materials that allows for the fabrication of high-precision fringes or dots with a periodicity between 5 μm and 650 nm. Processing of crystalline silicon and germanium results in the formation of precise periodic amorphous nanostructures, with topography profiles that depend on the period, laser wavelength and pulse duration. Femtosecond-resolved microscopy measurements reveal the presence of molten material reorganization processes as Marangoni flow, surface capillary waves and Plateau-Rayleigh instabilities. Ablative patterning of thin gold thin films shows potential for the generation of second harmonic upon pumping.

High quality poly(methyl methacrylate) (PMMA) thin nanocomposite films doped with different concentration of silver nanoparticles are demonstrated by using new optimized synthesis protocols. SEM and TEM confirmed the presence of Ag-PMMA nanocomposite nanoparticles of average size 10 nm with excellent dispersion of Ag nanoparticles into the PMMA matrix. By using a direct Laser writing system with a continuous wave 405 nm diode laser source the films were exposed and the non-linear nature of the plasmonic-based light absorption-energy transfer mechanism allowed formation of hole-like or linear patterns below 200nm, in the sub diffraction limit regime of the 280 nm FWHM laser beam, for the first time, suggesting the potential for nanocomposites sub-diffraction diode laser processing.

Surface structuring is a powerful technique for modifying material surfaces at micro and nanoscale to tailor their physical, chemical, or biological properties. In this study, we investigated wrinkle formation on amorphous GeTe films capped with various SiN layers (from 10 to–50 nm thick, in 10 nm increments) deposited on Si substrates. After magnetron sputtering, the SiN layer acquires compressive stress, with two configurations: low stress (428–650 MPa) and high stress (958–1070 MPa). Femtosecond laser irradiation (Satsuma laser, 1030 nm, 350 fs, 4 W) melts the GeTe layer, allowing stress relaxation in SiN and inducing surface wrinkles with submicron periodicity and nanometer scale amplitudes. The periodicity of these wrinkles depends on the SiN thickness, residual stress, and film mechanical properties. Using a flat top laser beam, uniform wrinkle patterns were achieved. Atomic force microscopy (AFM) and batch-wise FFT analysis quantified the wrinkle height and spatial frequency, enabling a direct correlation between morphology and material parameters, demonstrating tunable surface patterning via mechanical and laser induced effects.

Ultrafast laser processing enables localized photopolymerization in PVA/AA materials, allowing precise tailoring of surface morphology. In this work, we study the response of these photopolymers to high repetition rate (1 kHz–1 MHz) ultrafast laser irradiation (fs–ns) at 515 and 1030 nm wavelengths. The enhanced photopolymerization efficiency achieved with ultrafast laser sources lead to the formation of surface relief structures with micrometer scale heights. By tuning the irradiation parameters, arrays of periodic microstructures and diffraction gratings were fabricated and optimized to achieve maximum diffraction efficiency, observing a transition between surface-relief and refractive-index modulation regimes by tuning the repetition rate. These findings demonstrate the versatility of PVA/AA photopolymers for ultrafast laser structuring, with potential applications in micro-optics, diffractive elements, and biomimetic surface design.

This study investigates the bactericidal properties of ternary Zr-Cu-Ag thin film metallic glasses (TFMGs) after femtosecond laser texturing. Laser-induced periodic surface structures (LIPSS) significantly enhance antibacterial activity, preventing bacterial proliferation. Microscopic chemical and crystallographic changes at the surface are analyzed using Scanning Transmission Electron Microscopy and high-resolution Energy Dispersive X-ray spectroscopy, correlating these with ion-release measurements to elucidate the underlying mechanisms. The influence of the atmosphere during laser irradiation is also examined. Our findings highlight the potential of laser-modified TFMGs for antibacterial applications.

We study nanosecond laser colouring of commercially pure titanium in atmospheres with controlled O₂/air ratios. By varying oxygen concentration, laser power, and scanning speed, we quantify their influence on oxide growth and resulting colours. An interference-based optical model links oxide thickness and composition to measured reflectance spectra. We show that higher oxygen concentrations accelerate oxide formation and modify oxidation states, enabling a broader and more saturated colour gamut than ambient-air processing. Simulated spectra agree well with experiments, confirming the model. These results highlight controlled oxygen enrichment as a key parameter for efficient, predictable, and wide-gamut laser colouring of titanium for decorative and functional applications.

Climate change is one of the greatest and most urgent challenges of our time. If we want to keep the planet livable, greenhouse gas emissions must be net zero by 2050. Food production is responsible for up to a staggering 34% of greenhouse gas emissions. At the same time, our food production is highly sensitive to climate change and this is already having a major impact on the food system, such as crop failures due to extreme weather conditions. As a result, food security and food sustainability are top of mind. Technology can and will make the difference. The unprecedented convergence of AI, gene editing, DNA synthesis and biotechnology will revolutionize global industry, particularly in the agrifood domain. This presentation will show how optical sensing in general and photonic integrated circuits in particular are unique and indispensable technologies that provide solutions for farmers, food processing industry and consumers, and will help guide the transition of our food ecosystem to a more secure and sustainable industry. New tools in barns, in greenhouses, in orchards, in protein bioreactors and the accompanying digital twin AI technology will be shown.

Spectral imaging has long promised to uncover physiological and molecular information invisible to the human eye. Yet, despite decades of innovation, its translation into clinical routine has been slow. Beyond regulatory hurdles, challenges such as ill-posed inverse problems, data scarcity, and the demand for real-time analysis have repeatedly stalled progress. In this keynote, I will present recent breakthroughs at the intersection of computational biophotonics and machine learning that are reshaping the field. I will discuss how we combine spectral imaging with deep learning to achieve real-time tissue characterization in surgery and intensive care. Case studies will illustrate how spectral imaging can enable context-sensitive, clinically actionable support during interventions, transforming invisible spectral signatures into robust biomarkers. I will highlight not only our successes but also the failures that have shaped them. From spectral unmixing approaches that collapsed under distribution shifts to algorithms that failed spectacularly in the operating room, I will show how negative results became the foundation for new strategies. By dissecting what went wrong, we discovered how to adapt models across species and sensors, quantify uncertainty in predictions, and build validation frameworks that hold up under clinical reality. By putting the spotlight on failure—and how it fuels methodological innovation—I will argue that embracing negative results is the key to moving spectral imaging, powered by AI, from promise to practice. The future of the field may not depend on avoiding failure, but on failing better.

Femtosecond laser processing in GHz-burst regime offers enhanced control of thermal effects, enabling faster and more precise material modification. This work highlights three implementations demonstrating its versatility: (i) fabrication of moulds for microfluidic devices, (ii) high-throughput drilling of through-glass vias (TGVs), and (iii) surface treatment of 3D parts using a robot-assisted fibre-delivered system. All demonstrations use a 50-W, 1030-nm Satsuma X laser (Amplitude). For microfluidics, GHz-burst machining produces moulds with sub-10-µm accuracy and surface roughness below 300 nm, reducing production time to under an hour and cost to a few hundred euros. For microelectronics, the technique drills high-aspect-ratio holes (AS > 150) in fused silica in under 12 ms per hole, greatly improving throughput. Finally, the low pulse energy of GHz bursts enables stable fibre delivery. A hollow-core fibre mounted on a robotic arm transported up to 20 W while performing surface treatments on a 3D stainless-steel part.

Femtosecond laser processing enables precise micro- and nanoscale structuring of metallic surfaces, offering significant potential for biomedical applications such as titanium-based implants. This work investigates the flexibility provided by dynamically changing the spatial beam shape between successive laser passes during multi-pulse surface texturing. Our method alternates between different profiles within the same sequence, expanding the range of achievable surface geometries . Experimental characterization reveals that combining multiple beam shapes enhances structural complexity compared to single-shape strategies. We analyze the influence of beam overlap and spatial configuration on ablation patterns using quantitative surface measurements. Empirical ablation modeling and simplified thermal simulations are employed, offering insight into material removal and heat accumulation mechanisms. Our results demonstrate that multi-shape beam strategies represent a promising route for advanced ultrafast laser-based micro/nanostructuring for enhanced biomedical implant performance.

The choice of the mean laser power for a fast fs laser process is strongly corelated with the beam engineering process strategy: whether the focus is on the pulses repetition rate (faster deflection of the beam with a high-speed scanner) or on the pulses energy (beam division) and how to distinguish between technical limitations of the tools used (scanner, diffractive optical elements) and physical limitations (thermal or non-thermal nature of physical mechanisms involved, and appearance of associated thermal effects depending on the parameters chosen for the process). High speed scanning ablation results on metallic and semiconductor materials will be compared with ablation performed by lines of spots, ranging from 1 to 50. A variation of the total fluence from 1 J/cm² up to 80 J/cm² is considered as well as several number of passes. The processing speed obtained will be compared with simulations to validate possible estimation of the processing time.

In order to reduce drag and improve the ecological impact of industrial components, the BILASURF European Project focuses on developing and integrating a method for high-speed laser functionalization of complex 3D surfaces using tailored designed riblets for each application, while ensuring a high production rate through inline monitoring features. The process will be demonstrated in hydro-turbines and industrial fans. As the size and period of the riblets depend on each application, a machine prototype has been designed and manufactured including two different technologies to cover a wide range of riblet periods: Direct Laser Interference Patterning (DLIP) for periods up to 44 µm, and Direct Laser Writing (DLW) for larger periods. A custom designed acoustic monitoring system, which tracks the focal plane position inline, helps in maintaining a high throughput throughout all the process.

In this work, we explore advanced methods for liquid guidance enabled by surface microstructures fabricated using Direct Laser Interference Patterning (DLIP) with nanosecond and picosecond laser sources operating at UV and IR wavelengths. A first focus lies on the texturing of metallic stamps by ps-DLIP and their subsequent use in a hot embossing process to pattern pillar-like structures on PTFE. The fabricated topography strongly favored water-repellency characterized by water contact angles beyond 160°. Directional liquid transport driven by anisotropic wettability contrasts was proven on soda-lime glass by combining ns-DLIP to produce hydrophilic surfaces and spraying with a chemically active perfluoropolyether compound to induce hydrophobicity. Finally, spontaneous droplet motion without external actuation has been demonstrated on stainless steel by fabricating microtextures with varying spatial periods. When water droplets were placed on these gradient textures, the droplets moved in the direction of increasing periodicity, or equivalently, increasing hydrophilicity.

The general trend for miniaturization leads to widespread use of micro-optical elements for various applications including optical communications, embedded photonic systems, beam shaping and imaging. We propose here a cost-effective manufacturing method for complex 3D micro-optics based on femtosecond laser-manufactured of simple glass preforms that are topologically transformed into complex 3D objects with optical surface quality through a localized laser-induced viscous flow of the surface. Using this principle, we show that non-trivial shapes with non-rotational symmetry can be obtained. Finally, we introduce a simulation framework that predicts the topological transformation of these objects that we compare to the actual surface and optical properties of the experimentally produced specimens.

Imaging dishes and chambers are essential tools in microscopy, especially for live-cell studies. They are widely used due to their easy and cost-efficient production via injection molding and the advantageous properties of polymers, such as biocompatibility and optical transparency. A major challenge in cell research is single-cell analysis, which provides a more precise understanding of cellular mechanisms and population heterogeneity. This process involves distributing cells in spatially separated microcavities. Our study presents an efficient, large-scale approach to fabricating functionalized imaging dishes by combining ultra-short pulse laser processing with injection molding. We fabricated honeycomb-like cavities (100 µm in diameter) and microgrids (10 µm in line width and less than 1 µm in depth) on cyclic olefin polymer (COP) surfaces. This method enables the replication of existing structures and the integration of microgrids for the spatial control of cell populations. The combined process significantly reduces manufacturing time and cost while adding new functional capabilities.

The adoption of glass substrates is highly anticipated in next-generation semiconductors, but the extreme hardness and brittleness of glass make machining challenging. Laser processing is promising, yet conventional methods take tens of seconds to drill a single micro through-hole (depth over 1 mm and diameter less than 100 µm). Here, we demonstrate that combining the Transient and Selective Laser (TSL) processing method with a Bessel beam enables ultrafast drilling—one million times faster than existing methods. A 5 ps Bessel-shaped pulse creates a transient excited channel, followed by selective absorption of a microsecond pulse, forming a 3 µm-diameter through-hole in 20 µs. This breakthrough opens new paths for glass-core semiconductor substrates.

We report on in bulk modifications induced by Bessel-beam irradiation in Sodalime glass with a single GHz-burst. By coupling a single pulse probe with a burst pump, clear understanding of the accumulation regimes can be established. A comparison is also made between the bulk modification generated by MHz- and GHz-burst.

Sapphire has many advantages over other materials commonly used for direct laser writing of optical phase elements. These include excellent thermal stability and conductivity, broad transmission spectrum, high optical damage threshold, chemical inertness, and nonlinear properties, which could lead to interesting interplay with various phase elements. The issue arises when attempting to fabricate phase elements – the aforementioned high optical damage threshold means a high intensity is required for direct laser writing. This leads to many problems, such as cracking, nanograting formation, and induction of significant mechanical stress, all of which prevent using the material's beneficial properties. We share our research into the fabrication of phase elements in sapphire, which shows that ultrashort UV laser pulses significantly reduce the induced stress and likelihood of cracking. We show fabricated high-quality photonic crystal spatial filters and diffraction gratings as examples of phase elements.

We report on large-scale (2”), crack-free, and high mechanical strength transparent welding (> 360 MPa) of thick fused silica substrates (10 mm) using an ultrafast laser emitting 500-fs pulses at a wavelength of 1030 nm. The influence of scanning strategy is discussed in terms of joint quality and morphology. Shear stress and fatigue resistance measurements were carried out using a direct and glue-free method.

Phase-only beam shaping with a spatial light modulator (an LCoS SLM) enables the efficient generation of multiple laser spots in three dimensions. Beyond enabling parallel processing for bulk femtosecond laser micromachining of transparent materials, simultaneous machining also leads to overlapping pressure waves originating from the multiple spots. Here, we present experimental results of permanent structural changes in fused silica due to the interaction of these pressure waves and we discuss on their impact for parallelized multi-spot manufacturing.

Femtosecond lasers are key tools for 3D processing of transparent materials, but the stress waves they generate can degrade quality and induce cracking. We present a systematic study of stress-wave dynamics in fused silica using 1030-nm, 360-fs pulses with energies from 250 nJ to several μJ. Pump–probe microscope–polariscopy, combined with in situ intensity imaging and multiphysics simulations, enables high-resolution characterization of stress evolution. We find that stress-wave amplitude exhibits a logarithmic dependence on pulse energy, governed by peak-intensity clamping and consistent with simulations. These results establish a quantitative link between localized laser intensity and mechanical response, offering predictive insight for ultrafast laser processing.

Non-diffracting ultrafast Bessel beams provide an extended focal depth, enabling single-pulse formation of channels several hundred micrometres in bulk glass. When operated in regimes where near-field and far-field interactions coexist, the achievable structure size can be reduced to only a few nanometres, allowing fabrication of surface trenches on glass with a width below 10 nm. In this study, we perform glass cutting using ultrafast Bessel beams under conditions optimized to enhance near-field interactions to realize high–aspect ratio nanoscale structures. By tuning pulse duration, pulse energy, polarization, and scanning pitch, trenches approximately 100 µm deep and only a few nanometres wide are achieved. This results in the glass cut surfaces exhibiting significantly reduced roughness, demonstrating the capability of ultrafast Bessel beam processing to surpass current precision limits for extreme nano-structuring in glass.

Ultrafast Bessel beams are well recognized for enabling efficient processing of dielectrics thanks to their propagation-invariant focus. We show that single-shot irradiation of glass or fused silica with higher-order Bessel beams generates ultra-long nano-wires, about 200 nm in diameter and up to millimeters long, through a vapor-driven jet of molten glass. Scanning the beam produces a nanofoam-like layer of interwoven nano-wires. This simple approach opens new perspectives for fabricating complex 3D nanofoam materials for nanophotonics, electrodes, and catalytic applications.

Temporal shaping of femtosecond laser pulses for materials processing applications bring additional laser-matter interaction processes that trigger material modificaitons in the way of controlled energy absorption in dielectrics, deeper structural changes in semiconductors, and reduced ablation thresholds in metallic materials, opening new pathways for high precision material processing across many disciplines and fields of application.

We investigate the combination of a 40 MHz burst-mode ultrashort-pulse laser with a negative interburst overlap strategy to achieve high-speed welding of glass plates, both with and without optical contact, and for air gaps up to 3 µm. The laser source is a commercial 50W femtosecond laser (Amplitude) operating at a wavelength of 1030 nm with a pulse duration of 400 fs. Negative overlap between successive bursts is realized using a low repetition rate on the order of tens of kilohertz and a high scanning speed of 1 m/s. This strategy allows to make a discrete welding, for which each welding spot is caused by a single burst. Focusing is achieved using an f-theta lens with a 50 mm focal length, leading to a 30 µm spot size. The proposed approach demonstrates that only 40 µJ per burst is necessary to achieve the welding, what would be not enough to weld with a single pulse. This method has potential for a significant scalability, and with the use of industrial grade laser with higher average powers, welding speeds approaching 100 m/s could be possible.

Femtosecond laser welding enables precise bonding of transparent polymers via multiphoton absorption, minimizing thermal effects while maintaining high spatial control. This paper investigates how scanning speed and the number of passes affect the shear strength of polycarbonate joints welded using a 1030 nm femtosecond laser. Experiments were performed at speeds of 10–100 mm/s with two pass levels, maintaining a 1 MHz repetition rate and a 21 µm spot diameter. The fluence was optimized to prevent focus offset and ensure stable interfacial energy deposition. Results show that increasing the number of passes generally decreases shear strength due to excessive seam widening without proportional load-bearing improvement. The highest strength of over 30 N/mm² was achieved at 30–50 mm/s with low passes, while an effective speed analysis identified 7.7 mm/s as the best trade-off between strength and throughput. The findings enhance understanding of parameter interactions in femtosecond laser polymer welding.

We will present recent advances in ultrafast laser micro-welding (ULMW), focusing on we use it to create hermetic seals for quantum technology, such as miniaturised ion traps for quantum networking. With our main target being welding silica-based crown glass to titanium grade 2, we produced robust hermetic samples, reaching helium leak rate below 10-10mbar∙l/s. This important first step opens the door to a new and efficient way to produce miniaturised quantum systems.

Ultrafast laser processing offers unique opportunities for micro- and nanoscale structuring of metallic surfaces, particularly for biomedical applications. In this work, we explore femtosecond laser pulses that are spatially shaped and temporally controlled to achieve precise surface texturing on titanium alloys. Beam shaping is performed using a Spatial Light Modulator (SLM), enabling complex profiles such as vortex beams. However, imperfections in the SLM introduce parasitic diffraction orders and residual phase errors, which compromise the fidelity of the laser-material interaction. We experimentally assess the impact of these artifacts on surface morphology through quantitative analysis. Deviations from the ideal beam profile result in irregular patterns and reduced reproducibility, with vortex beams showing being highly sensitive to phase distortions. These results underline the critical role of beam-shaping accuracy in achieving predictable and controlled surface features.

Multispectral filter arrays enable compact spectral imaging but typically require complex, multi-step fabrication. We demonstrate a single-step holographic grayscale lithography method that uses SLM-generated holograms to directly write Fabry–Perot filter arrays with cavity thicknesses spanning 600–1300 nm in one exposure. Transfer-matrix modelling with Monte Carlo averaging captures thickness variations, and experimental spectra fitted via Tikhonov-regularized inversion show strong agreement with simulations (R² ~ 0.95). We further show that speckle, usually a limitation in projection systems, can be harnessed to controllably broaden Fabry–Perot resonances. The technique achieves 1–2.5 μm lateral resolution, comparable to commercial direct-write lithography, while consolidating multiple fabrication steps into one. This offers a scalable, tunable route toward CMOS-compatible multispectral filter arrays.

Adaptive Optics serves as a precise and facile means of laser beam shaping that is opening new directions for three-dimensional nano-structuring inside of transparent materials. A Fourier synthesis method in shaping generalized Bessel beams was employed in optical simulation and replicated in experimental characterization. The beam shaping approach generated precise sub-micrometer transverse dimensions scaling to 400-800 nm diameter Bessel beam filaments and demonstrated high fidelity control over axial intensity profile such as flat, sine wave, and parabolic shapes. The beam shaping approach is applicable to other forms of diffraction-less beams such as helical and Matthieu beams. The application of variational calculus approaches in the spatial light modulator phase optimization algorithm facilitated record diffraction efficiencies in a range of ~20 to 50%. The practical demonstration relied on application of Zernike aberration correction to compensate for astigmatism and other aberration in the source laser beam (515 nm) and the optical system.

We present an ultrasound-tunable liquid-metal mirror for dynamic and damage-resistant beam shaping of high-intensity lasers. A reflective liquid surface is precisely deformed by using focused ultrasound waves, enabling real-time and programmable light control, including point-focused and ring-shaped beam patterns with tunable focal lengths (600 mm to 25 mm) and feature widths (120 μm to 20 μm). Validated for laser ablation of carbon films, this approach is a robust and reconfigurable method for tailored high-intensity laser materials processing.

Beam shaping by focusing high-power modern TEM00 lasers to create flat-top, “doughnut” or “inverse-Gauss” spot profiles should provide resistance to high-power laser radiation, stable transformation of irradiance distribution. To minimize or eliminate undesirable thermo-optical effects of thermal focus shift and thermally induced spherical aberration, it is proposed the refractive beam shapers with smooth optical surfaces, which transform the Gaussian profile of TEM00 beam into a beam with the Airy disk intensity distribution and a specific phase profile, are implemented from sapphire or crystalline quartz, characterized by high thermal conductivity or self-compensating thermo-optical effects. Features of the approach include beam shaping with extended depth of focus, stable operation with multi-kW lasers, easy integration in equipment, simple adjustment and switching between profiles. Design features of refractive beam shapers, results of profile measurements and material processing are presented.

Laser powder bed fusion is widely recognized as a powerful method for building high-temperature materials into complex 3D architectures with precise control and digital programmability. Traditionally, this process preserves the chemistry of the starting powders through simple melting and resolidification. In our work, we take a different approach—using the laser not only for shaping but also to drive chemical transformations in a precursor powder, creating new multiscale structures and material properties. Specifically, we demonstrate the fabrication of graphitic aerogels (GAs) by combining powder bed fusion with localized pyrolysis of hemoglobin, a protein-rich biowaste. This process enables direct writing of monolithic GAs with centimeter-scale dimensions and provides control over the micro and nanoscale structure of the material. By leveraging the layer-by-layer nature of powder bed fusion, we can design hierarchically porous architectures with tunable properties across multiple length scales and show how these materials deliver exceptional energy storage characteristics in 3D printed supercapacitor applications.

With a novel precession module and five-axis stage, this research investigates the effect of varying taper angle on the performance of 3D lithium-ion batteries. Diverging, parallel and converging side walls are manufactured via femtosecond laser ablation, using a precession module, allowing the variation of incident angle of the laser beam onto the sample. This is characterized and verified by laser scanning microscopy, providing three-dimensional images of the ablated features. The highly promising lithium manganese iron phosphate (LMFP) is used as cathode material. The performance of different structures is tested electrochemically in 2032 half-cell configuration. The accessible capacity at different charging speeds (up to charging rates of 5C), as well as the long-term stability are tested and the different structures are compared.

We report on a comparative study of MHz and GHz bursts for femtosecond laser structuring of electrodes (graphite-silicon composite and high nickel content NMC coatings). Influences of average power, burst length and intra repetition rate on the matter removal rate were investigated for drilling and grooving with both holes and grooves reaching the metallic collector. Removal rates and resulting machining qualities, investigated by SEM, were compared between single pulse (SP) and bursts (clocked at 40 MHz and 1.28 GHz). Fastest processing conditions for which SP and burst machining qualities are comparable were identified by SEM. In accordance with an ablation model, results indicate that removal rates depend strongly on the burst duration and slightly on the intra-repetition rate. MHz and GHz burst modes can decrease the processing time by a factor up to respectively 4 and 5.

A quantitative analysis of laser-induced breakdown spectroscopy (LIBS) for lithium iron phosphate (LFP) electrodes was established to study the three-dimensional elemental concentration distribution and to optimize electrode architecture. Due to the characteristic flat voltage curve of LFP, a full-cell model was applied for electrochemical titration, enabling the validation of quantitative calibration model on state of lithiation using IR laser radiation. To further enhance analytical throughput, a laser repetition rate of 500 Hz was applied, demonstrating the potential for high-speed, spatially resolved analysis.

This study employs LiMn0.7Fe0.3PO4 cathodes as active materials, with electrochemical performance enhanced by laser structuring. Ultrashort pulse laser ablation combined with GHz bursts enables high-throughput fabrication of precisely defined 3D electrode structures. The laser parameters, such as peak fluence and burst length are optimized to assess their effects on the laser processing quality and ablation efficiency. SEM is applied to examine potential thermal modifications of electrodes. Half-cells with structured and unstructured electrodes are assembled and analysed regarding rate capability.

In lithium-ion battery technology silicon is introduced as anode materials to further increase gravimetric and volumetric energy density. Silicon is a high-capacity anode material and offers one order of magnitude higher capacity than the commonly used graphite. During lithiation of silicon a volume expansion of up to 300 % cause high mechanical load and lead to a fast capacity fading. Customized 3D electrode architectures with different materials mixtures, multi-layered and structured electrode layers can significantly increase the cycle lifetime. Laser-assisted printing (LIFT) can support the further development of advanced electrode architectures. Two types of electrode architectures based on an optimized electrode ink were printed: silicon-containing multilayer materials with different layer configurations, and electrodes with segmented areas of different compositions. Especially the impact of patterns such as grid, hole, and line arrangements on the electrochemical properties was investigated in detail. Post-mortem analysis via SEM and laser-induced plasma spectroscopy were conducted.

Quantum-enhanced imaging is an emerging area of research with relevance to a wide variety of application areas, including transport, gaming, environmental research, and security and defence. This subject encompasses a range of techniques and utilizes a number of developing quantum technologies. Time-resolved single-photon imaging approaches have been used to reconstruct high-resolution three-dimensional images, including challenging scenarios such as imaging through atmospheric obscurants and clutter. Critically, this approach has been extended to imaging in turbid underwater conditions. In the past, image reconstruction often proved to be time-consuming due to the inherent computational complexity, however advances in algorithms and hardware have allowed examples of “real-time” reconstruction of moving targets. Single-photon imaging has been used in demonstrations of moving target identification and human activity recognition with the aid of artificial intelligence approaches. Alternative single-photon imaging approaches, such as ghost imaging, will also be discussed.

I will present the PIXEurope Pilot Line, a recently started 400MEuro initiative under the Chips JU, that aims at developing and transferring advanced photonic integrated circuit (PIC) technologies and processes. Through Open Access, PIXEurope will support end-users in increasing the readiness level of their products. I will also present some technologies, leveraging PICs, that were developed at ICFO and transferred to spin-offs, now commercializing quantum random number generators, cryptography systems and phase imagers. Biography: Valerio Pruneri is an ICREA Professor and Corning Inc. chair, leading the Optoelectronics group at ICFO. He is also the Director of PIXEurope Pilot Line. Previously he worked for Avanex, Corning, Pirelli, and the University of Southampton. With his groups in academia and industry, he has developed technologies for the photonic, photonic integration, and quantum. He is inventor in more than 70 granted or pending patent families, leading to numerous industrial collaborations and the creation of four spin offs, Quside, Sixsenso, Luxquanta and Shinephi.

To address the controllability challenges of intense femtosecond laser pulses in semiconductors, we investigate a range of spatial and temporal optimization strategies to advance three-dimensional laser-writing technologies. We introduce an elegant approach for in-volume interactions using tightly focused, counter-propagating infrared pulses through a single lens. The cooperative effect between the two beams enhances bulk excitation conditions within silicon. To achieve highly localized and reliable processing, we employ a multi-timescale irradiation scheme in which pre-ionizing femtosecond pulses generate critical plasma seeds that synchronize with subsequent writing pulses. This approach enables isotropic, ∼1-µm-sized modifications inside silicon. Notably, it also leads to a substantial improvement in the controllability of material transformations, enabling unique demonstrations such as rewritable optical memories (exceeding 100 writing/erasure cycles) and graded-index functionalities. These results highlight promising pathways toward precise 3D laser processing solutions and the fabrication of reconfigurable, monolithic silicon-based devices.

Ultrafast lasers at 2 µm wavelength have strong potential for material processing. For example, the long wavelength enables in-volume modification and backside-machining using the transparency window of semiconductors. While research laboratories have conventional access to SWIR via optical parametric amplifier systems, these remain impractical for industrial application demanding simple and robust sources. Such sources can be obtained from Thulium (Tm)- or Holmium (Ho)-based lasers emitting around 1.9 µm and 2.1 µm wavelength, respectively. Tm-doped fiber lasers excel at low energy and high average power, while Ho-doped bulk lasers offer high energy scaling potential and high average power. The higher pulse energies accessible in a bulk laser architecture are beneficial for compensation of the substantial losses of beam shaping and high-NA focusing. In this contribution, we first present a holmium-based ultrafast bulk lasers for scientific and industrial users and then discuss first material processing tests with such an amplifier system translating the benefits of SWIR lasers from the laboratory to the factory floor.

We present a flexible laser-based approach for large-area material nanostructuring that combines colloidal lithography with spatially addressed photonic nanojets (PNJs) under microspheres. A self-assembled monolayer of 5 μm polystyrene spheres serves as microlenses for 1030 nm femtosecond laser pulses, producing sub-diffraction near-field spots (<500 nm) on silicon surfaces. By employing a custom motorized rotational setup, controlled irradiation at varying incident angles enables precise and parallel writing of arbitrary nanopatterns. Careful calibration and compensation measures ensure stable and reproducible exposure conditions with the scanned nanobeams. The method allows the fabrication of ultra-dense surface features in both amorphization and ablation regimes, achieving feature densities up to ~5 × 10⁶ cm⁻². FDTD simulations confirm the precision and scalability of the approach leading to a suitable method for the fabrication of photonic devices, metasurfaces, and optical data storage platforms.

The research work presents silicon laser processing with GHz bursts (emission wavelength at 1.6 um) for uniform column growth throughout the bulk of a 1 mm sample. Different burst configurations and burst parameters are explored for repeatable uniform column growth. While 2 pulse per burst was observed to be better compared to single pulse in terms of column growth, the energy distribution within the 2 pulses too have an effect on such modifications. Thanks to the optimization of different parameters, columns are generated with writing speeds such as 7 μm/s even in the absence of substrate glass.

Advancements in semiconductor packaging are essential to improve high-bandwidth memory (HBM) and AI systems. Laser lift-off (LLO) enables glue-free release and reuse of fusion-bonded silicon carrier wafers using short-pulsed infrared beams. A focused Gaussian laser beam mode resulted in the released wafer surface with total thickness variation (TTV) greater than 100 nm, which effected sequent reuses. The defocused ring-shaped vortex beam resulted in through-put increase to contribute for cost reduction and environmental sustainability of the LLO process. However, LLO can induce thermal and mechanical stresses that risk device integrity. To establish safe process windows, thermal damage mechanisms were analyzed using X-ray diffraction and Raman spectroscopy to detect silicide phase transitions below 500 °C and calibrated with rapid thermal annealing. Experimental data were coupled with stack-level absorption and heat-transfer simulations, enabling validation of acceptable energy exposure across material stacks. This combined experimental–simulation framework enables optimized stack engineering, ensuring device integrity and sustainable wafer reuse in advanced packaging.

Single-crystal silicon carbide (SiC), as a pivotal third-generation semiconductor material, exhibits extensive application potential in fields including 3C electronics and MEMS devices. The manufacturing of single-crystal SiC micro-vias represents a key enabling technology for advanced 2.5D and 3D packaging, analogous to Through-Silicon Via (TSV) technology. In this work, the effects of fundamental femtosecond laser parameters on the generation of surface defects (e.g., cracks and fractures) during femtosecond laser drilling were systematically studied. The research also elucidates the intrinsic correlation between the direction of crack generation, the crystalline orientation of SiC, and the laser polarization direction. Ultimately, defects including cracks and fractures were effectively eliminated via polarization modulation and optimized processing techniques.

Ultrashort laser pulses focused inside optical glasses enable localized transformations in volume. For example, isotropic index modifications, so-called Type I, can be used to fabricate complex waveguiding structures, gratings, lenses. Another type of transformation, labeled Type II or nanogratings (NGs), corresponds to the formation of sub-diffraction porous nanostructures controllable by light polarization. NGs are birefringent, making them attractive to the development of 3D geometric phase components, waveplates, optical data storage, or fiber-based sensors, e.g., Fiber Bragg gratings (FBGs). Furthermore, NGs exhibit extraordinary thermal stability, withstanding hundreds of hours at 1000°C, making them particularly useful for FBGs operating in harsh environments. To date, fs-Type II FBGs are principally inscribed in telecom, lightly doped, silica core optical fibers. When operating at high temperatures (>800 °C), NGs progressively relax and erase, causing drifts of the monitored property (e.g., Bragg wavelength), and more drastically a loss of signal. Therefore, there is a need to comprehend and predict what drives NGs erasure over a given thermal treatment, to anticipate potential signal degradation. Following this, novel solutions must be envisioned to go beyond current limitations, ultimately set by the intrinsic nature of the glass substrate, usually SiO2.

We demonstrate densely integrated photonic devices on glass substrates using adaptive optics-assisted femtosecond laser direct writing. By enhancing refractive index contrast (> 0.01), we achieve minimal crosstalk at waveguide spacings of 15 µm. Novel designs for fully straight directional couplers and interferometers are presented and experimentally verified at telecom wavelengths, enabling chip-scale integration without waveguide bends.

The realization of strong photonic stopbands in optical fibre over extremely short device lengths requires high refractive-index contrast and subwavelength precision in nanostructure placement, while preserving the mechanical robustness of the fibre. We report refined nano-hole assembly techniques that produce densely spaced, first-order periodic arrays of nano-capillary fibre Bragg gratings and enable two-dimensional photonic crystal formation across the fibre-core waveguide, while mitigating stress-induced cracking. These compact in-fibre photonic crystal structures yield stronger and broader photonic stopbands, achieved over device lengths far shorter than those of traditional fibre Bragg gratings. The resulting low-insertion-loss devices open new opportunities for spectral shaping and filtering in fibre-optic and lightwave circuit applications.

High-finesse optical microcavities are at the core of a wide range of scientific advances and technical applications from quantum technologies to optical sensors. Among them, fiber Fabry-Perot cavities (FFPCs) are of particular interest because of their unique properties. However, integrating FFPCs into photonic devices remains an experimental challenge prone to errors. To tackle this limitation, we combined FFPCs with femtosecond laser manufacturing to assemble an all-glass FFPC integrated on a microstructured glass substrate with a reduced footprint (25x25 mm). Cavity finesse reached prior to fine tuning exceeded 60 000. Post-assembly fine tuning is performed only once. Our manufacturing approach paves the way for miniaturized ‘all-glass’ FFPC chips with extreme sensitivities that can be deployed outside the labs finding applications in gas sensing applications and quantum technologies.

Sub-100 fs pulses are desirable for various applications in glass micromachining and there exist several devices for retrospective pulse compression. The physical process behind the compression mechanism influences the pulse characteristics, in particular its temporal shape and the broadened spectrum. We investigate the impact of two compression methods on fused silica micromachining: Optical parametric amplification generates a tuneable almost Gaussian-shaped spectrum with low conversion efficiency. Self-phase modulation within a multi-pass cell broadens the spectrum with oscillations around the initial wavelength with almost no losses for the pulse compression.

Gold nanoparticles display size-, shape-, and aggregation-dependent plasmonic properties. Pulsed Laser Ablation in Liquid (PLAL) enables chemical-free synthesis of small, stable Au NPs, while halides such as bromide induce controlled aggregation into linear chains. The aggregation kinetics depend on halide type, concentration, temperature, and particle size, as shown by UV–Vis spectroscopy and electron microscopy. Pulsed laser re-irradiation dynamically modifies these assemblies: low fluences gradually disrupt chains, whereas higher fluences induce simultaneous chain disruption and nanoparticle fragmentation, especially under resonant excitation at the transverse LSPR (∼532 nm). Ultrafast pump-probe spectroscopy reveals that electronic relaxation times increase with particle size and clustering, linking plasmonic coupling to energy dissipation. This work demonstrates dynamic, laser-enabled control of Au NP chains, integrating synthesis, assembly, ultrafast dynamics, and optical reshaping for applications in photonics and advanced manufacturing.

We present a novel volumetric 3D printing platform using a phase light modulator (PLM) to enhance efficiency in holographic tomographic volumetric additive manufacturing (Holographic TVAM). Unlike traditional amplitude-based systems, PLM-based phase encoding boosts laser power efficiency 70-fold. Combined with speckle reduction, this enables rapid fabrication of complex 3D structures across scales (microns to centimeters) and materials including cell-laden hydrogels (1M cells/mL). We also introduce gelatin Thiol/Norbornene as a printable resin, achieving large-scale prints (~ 3.8 × 3.8 × 4 cm3) in under 2 minutes using a low-power 150 mW UV laser diode. This approach opens new possibilities for scalable, high-resolution light-based 3D printing.

This study demonstrates Laser-Induced Forward Transfer (LIFT) as a high-precision digital tool for fabricating components for stretchable bio-sensors. LIFT was used to print silver nanoparticle inks as fine interconnections (30-50 μm) and gold inks for graphene bio-sensor source/drain electrodes onto flexible substrates. Laser printing and subsequent sintering processes were optimized to enhance electrical conductivity while preserving substrate mechanical properties. The method produced smooth, defect-free and ultra-thin patterns with high conductivity, meeting the demands of stretchable electronics. This work highlights LIFT's significant potential for manufacturing the next generation of advanced bio-sensors and flexible electronic systems.

This work will introduce two strategies for increasing the productivity of 2PP based on the use of advanced optics to parallelize the writing process leading to the fabrication of 3D microstructures by flushing with tens, or even hundreds, or points at the same time. These two will be based on using Spatial Light Modulators (SLMs), either in in imaging and Fourier configurations. The optimization of the projected light pattern for the fabrication of the targeted 3D features with the highest fidelity possible will be presented, demonstrating how, by using the adequate corrected image, both productivity and resolution of 2PP can be tackled at the same time.

Laser Induced Forward Transfer has been employed as a photonic and digital fabrication technology for the direct and high-quality assembly of 2D materials including graphene and 2D material semiconductors such as MoSe2 and MoTe2. The transfers have been carried out on test Field Effect Transistor devices and electrical characterization has been conducted to extract the resulting carrier mobilities. Additional characterization using Raman spectroscopy, AFM and SEM has confirmed the high quality of the of the transferred patterns.

Two-photon–induced photolysis enables localized deposition of platinum from a liquid precursor with sub-micron resolution onto a substrate. The nonlinear absorption within the liquid induces photodissociation of a precursor, leading to the formation of Pt nanoparticles that aggregate into nano- to micro-scale structures. We quantify how focus position, polarization, repetition rate, pulse energy and irradiation time affect the deposition process. The method offers a versatile route to 3D deposition of metals, for applications such as electrode deposition on non-planar substrates. This opens a number of applications in microelectronics, sensing, biomedical devices and photonics.

We report the use of Laser-Induced Forward Transfer (LIFT) for the deposition of eutectic AuSn thin films intended for flux-free bonding of optoelectronic components on photonic integrated circuits. Two solid-phase AuSn donors, with thicknesses between 100 nm and 500 nm, were employed to achieve LIFT printing of uniform, and well-defined pads on SiO₂/Si substrates while maintaining the eutectic composition. Subsequent flux-free bonding was performed using a 975 nm CW laser. Preliminary results demonstrate reproducible pattern formation, smooth morphology, and stable electrical behavior of the bonded structures. Ongoing work focuses on optimizing parameters such as melting point and joint strength, confirming that sub-2 μm LIFT-printed AuSn films offer a precise, low-thermal-budget route for advanced photonic integration.

Ultrafast laser processing enables the high precision structuring of polymer surfaces, especially at high repetition rates, where heat accumulation significantly influence the ablation efficiency. This work investigates the ablation behavior of commercial polymers (PVC, PET, PP and PDMS) under ultrafast laser irradiation (fs – ns) at 515 and 1030 nm, supported by complementary thermal modelling. Efficient ablation with minimized thermal effects was achieved in the sub-MHz regime, suggesting the onset of ablation cooling effects. The influence of laser parameters on the onset of these effects was also examined. These insights contribute to optimizing ultrafast laser micro-machining strategies for advanced polymer processing.

Femtosecond laser is a powerful tool for fabrication of microstructures in various substrates used in electronics manufacturing. We demonstrate the optimisation of the percussion drilling process for creating high-quality vias in glass and a wide bandgap semiconductor 4H-SiC. Remarkably, our results show excellent performance of repetitive single pulse drilling in glass with possibility to obtain high aspect ratio through glass via (TGV) with minimized taper and shiny walls. We show the influence of pulse repetition rate, pulse energy and pulse duration on the drilling process. On the other hand, superior performance 4H-SiC drilling was obtained using MHz bursts of pulses with the duration below 270 fs. The burst mode is an enabling factor for defect-free processing of 4H-SiC and boosting the drilling throughput. We demonstrate how tuning the burst length allows for increasing the throughput without compromising the spatial resolution and quality of the microstructures. Drilling of Si and 4H-SiC with full laser power of 30 W at 100 kHz repetition rate will be demonstrated. Experiments were performed at Fluence Ultrafast Laser Application Laboratory using Jasper X1 femtosecond fiber laser operating at 1030 nm.

Bessel transient and selective laser (Bessel TSL) processing enables high-aspect-ratio drilling in transparent materials. However, its application to alkali-free glass looks distorted compared to the fused silica. Here, we show that plasma-induced thermal loading near the hole entrance expands the electron-excited region and prevents the laser from propagating deeper into the material, resulting in instability. By reshaping the Bessel beam into a wider-angle configuration, the beam path avoids the plasma-affected region while increasing energy density. This enables stable, high-quality drilling in alkali-free glass, providing a viable approach for applying Bessel TSL to practical semiconductor packaging substrates.

We present a pulse-resolved LIBS sensor for real-time control of laser microvia drilling. Plasma emission is analyzed on application-specific single-line channels, with hardware-level reduction to one analog and one digital output per laser pulse at up to 2 MHz. The outputs command the laser and scanner in under 500 ns, enabling per-pulse control, adaptive scan paths, and selective material removal. Proof-of-principle on a two-layer copper PCB stack demonstrates that the system enables fully inline quality monitoring, real-time feedback, and full process traceability, opening the way for new high-speed laser processing applications.

Glass interposers are becoming popular for advanced electronics packaging, especially in low-volume, high-value applications. They help connect different types of chips on a shared platform, offering strong performance without needing complex single-chip designs. This work explores the creation of through vias in Schott Borofloat33 glass using selective laser etching. By adjusting the laser processing and chemical post-processing parameters, we achieved control over hole size, shape, and spacing. Our approach allows for tightly packed, high-quality interposers with high aspect ratio holes which will support flexible, cost-effective manufacturing for next-generation electronics.

The authors investigated the possibilities of generating clean cuts on NiTi foils using laser ablation in liquids to demonstrate the superiority of the cutting quality compared to processing in a gaseous atmosphere. Due to the minimal heating of the sample, this technique is well-suited for heat-sensitive materials. Further experiments using MHz pulse bursts as well as GHz pulse bursts show a dependence of the kerf flank topography on the burst parameters. The burst frequency as well as the number of sub-bursts have been varied to either generate clean cuts or intentionally create periodic microstructures of the cut sidewalls.

We demonstrate square-hole drilling in metals using a polarization-converting element. A cross-polarized beam was designed such that highly absorptive P-polarized light was positioned at the corners of the square intensity distribution in the focal plane, while less absorptive S-polarized light was distributed along the edges. This polarization configuration enables faster ablation at the corners than along the edges, promoting the formation of a square hole. Square-hole drilling was performed using a Ti:sapphire femtosecond laser system by a lens with a 50 mm focal length. We fabricated square through-holes with a thickness of 0.1 mm and a lateral size of 35 µm with static exposure. The results confirm the usefulness of polarization-controlled drilling for forming non-circular microholes in copper foils.

Control of intensity profiles is important in applications with powerful ultrashort pulse lasers. Specific requirements to beam shapers: variable intensity distributions, keeping the beam consistency, operation with TEM00 and multimode lasers, high resistance, – are fulfilled by refractive field mapping beam shapers realizing wavefront manipulation using lenses with smooth surfaces. Irregular profile of input beam can be corrected using an air gap. To avoid the air break-down in the intermediate focus in imaging optical system it is suggested using field lenses displacing the energy concentration point and increasing focus spot. The paper describes beam shaper designs and optical imaging layouts, presents experimental results.

Compensation for spherical aberration by 0.8NA focusing ultrafast pulse laser beams in media at depth up to 4 mm is a crucial technique in writing waveguides, nanostructuring, selective laser etching, optical data storage, slicing SiC. A suggested solution is aplanatic objective with function of compensating for spherical aberration, equipped with a replaceable protective window and capable to operate with various materials at 1030nm and 515nm. Over- and under-compensation of spherical aberration allows providing specific processing effects. The paper presents an analysis of high NA focusing inside a transparent medium at different depths, and experimental results for writing waveguides.

We have developed a technique for microfabrication of the thermoset polymer polydimethylsiloxane (PDMS) using a conventional nanosecond laser-induced bubble, termed microFLIB. In the 2D microFLIB process, microgrooves with hemispherical cross-sections can be fabricated on the PDMS surface. Furthermore, metal films can be selectively deposited along these grooves through subsequent electroless plating. In the 3D microFLIB process, hollow microfluidic channels can be embedded within the PDMS substrate. In addition, through-holes with high aspect ratios exceeding 200 can be fabricated by a single laser scanning. The developed microFLIB technique enables high-speed and high-quality microfabrication of PDMS, offering great potential for applications in microfluidic and biochip devices.

This study examines defect recognition in high-speed continuous-wave laser micro-welding of thin stainless-steel sheets. Using a three-channel photodiode system to monitor laser back-reflection, infrared, and visible emissions, optical signals were correlated with defect formation under dynamic conditions. The effects of laser angle, power, focus, and inter-sheet gap on signal behavior and defect sensitivity were analyzed. Distinct signal patterns were linked to specific defect types, and machine learning enabled high-confidence classification. The results demonstrate that integrated optical sensing coupled with machine learning can support real-time quality monitoring and defect classification in laser micro-welding.

Laser surface texturing enables superhydrophilicity on glass surfaces, but increased roughness often reduces optical transmittance due to enhanced scattering. In this study, two-dimensional (2D) periodic structures were fabricated on soda-lime glass using femtosecond laser ablation as an extension of our previous one-dimensional (1D) groove design. The effects of periodic spacing and laser parameters on contact angle and optical transmittance were systematically investigated. Compared with 1D grooves, the 2D structures exhibited lower contact angles at the same period, while showing a slight reduction in transparency. Superhydrophilic glass (contact angle < 10°) was achieved at a processed area ratio of approximately 6%, while maintaining high transparency (~89%). The results indicate that the processed area ratio is a key structural parameter governing the trade-off between wettability and optical performance. These findings provide structural design guidelines for ultrafast laser manufacturing of transparent functional glass surfaces.

Femtosecond laser irradiation of molybdenum surfaces was performed to study the evolution of laser-induced periodic surface structures (LIPSS) under controlled pulse overlap. Using 35 fs, 800 nm pulses at 1 kHz, pulse overlap was varied from 0% to 100% via electronic shutter control and nanoscale scanning. Distinct morphologies emerged: isolated HSFL without overlap, coexisting HSFL–LSFL at ~62%, and highly ordered LSFL under full overlap. In static irradiation, pre-structured surfaces generated by earlier pulses supported surface plasmon polaritons that interfered with the incident field, reinforcing periodic energy localization, leading to coherent LIPSS formation.

Femtosecond (fs) lasers are widely employed in precision micro-machining due to their ultrashort pulse durations and high peak powers, enabling material removal with high resolution and minimal heat-affected zones. This study investigates the ablation behavior of stainless steel and aluminum using two fs laser regimes: a GHz burst laser and a single-pulse fs laser. The GHz burst laser operated at a 2 GHz intra-burst repetition rate and 200 kHz burst rate under various burst durations, while the single-pulse laser operated at 400 kHz. Line scribing and single-shot ablation tests were performed to analyze how burst structure, repetition rate, and energy delivery affect ablation behavior.

The development of integrated photonics as a versatile platform for information transfer demands optical components with low loss, high precision, and scalability. Two-photon-induced photopolymerization (2PP) offers a promising alternative to lithographic methods due to its high resolution, low cost, and ability to incorporate dopants into polymer matrices. Tungsten disulfide (WS₂), with strong photoluminescence, mechanical robustness, and high second-harmonic generation sensitivity, was explored as an optoelectronic dopant for polymer-based whispering-gallery-mode microresonators fabricated via 2PP. Characterization techniques such as UV-Vis spectroscopy, fluorimetry, SEM, DLS, EDX, AFM, and Raman confirmed the successful integration of WS₂ nanoparticles. These results highlight potential of WS₂-doped 2PP microresonators for incorporation into advanced integrated photonic systems.

We present a novel, integrated module for real-time measurement of focal spot size and beam quality (M²) tailored to precision laser micro-machining applications. The device supports continuous-wave and ultrashort pulse lasers up to 100 W, featuring elaborate power attenuation, high-resolution imaging, and a motorized translation stage for detailed caustic analysis. This compact, versatile system enhances characterization accuracy, facilitating optimization of laser-based microfabrication and additive manufacturing processes.

Micro-machining with short-pulsed lasers is used to minimize thermal effects, as the heat-affected zone depends on pulse duration. This distinction between “cold” and thermal ablation holds for single-shot processes, but high-repetition-rate involves additional effects such as incubation, plasma shielding, and thermal accumulation, making the choice of optimal pulse duration more complex. This study compares laser cutting and engraving using sub-picosecond and nanosecond lasers across different repetition rates and powers. Experiments on graphite have been conducted to determine material properties and optimal processing parameter. Results highlight the influence of pulse duration and process parameters on efficiency and thermal effects, offering insight for high-rate laser processing of sensitive materials.

We present a photonic, mask-free, and solvent-free Laser-Induced Forward Transfer (LIFT) technique for the precise deposition of hBN and up to four graphene layers onto microstructured substrates. The method enables selective placement and patterning in a single step while preserving graphene’s crystallinity and electronic integrity. Electrical measurements using van der Pauw structures confirmed reliable extraction of sheet resistance, while photodetector devices exhibited tunable photoresponse dependent on graphene thickness. Optical, SEM, and Raman analyses verified structural uniformity and layer control. Furthermore, sequential LIFT printing of graphene–hBN–graphene stacks demonstrated stable, uniform heterostructures, establishing LIFT as a robust platform for scalable 2D material integration in optoelectronic and photonic systems.

In this work, we present a compact and power-efficient Direct Laser Interference Patterning (DLIP) optical configuration optimized for nanosecond-pulsed UV (266 nm) lasers. The system incorporates a galvanometer scanner for flexible beam delivery and a Köster prism on a motorized linear stage for beam splitting and for adjusting the texture spatial period. This new configuration allowed an improvement of the power efficiency from 69%, obtained in a conventional DLIP setup, to 87%. Simultaneously, the number of optical elements were reduced enabling a more compact optical configuration. This setup allows the fabrication of well-defined periodic line-like microstructures with variable spatial periods between 2 µm and 5 µm at throughputs of 87 cm2/min on polymer materials such as polyethylene terephthalate (PET) and polycarbonate (PC) as well as on soda-lime glass. The results demonstrate the potential of this approach to establish a more compact, cost-effective, and scalable platform for functionalizing transparent materials.

Sapphire is a promising material for advanced optical and sensing devices due to its excellent hardness, thermal conductivity, and transparency. The Bessel TSL (Transient and Selective Laser) processing method enables ultra-high-speed micromachining of transparent materials by combining an ultrashort laser pulse that forms a filament and a microsecond pulse selectively absorbed within it to induce ablation. Here, we applied this method to sapphire and investigated its machining behavior using high-speed imaging. A filament extending through a 320 μm-thick substrate was generated by a 1030 nm, 5 ps laser, and selective absorption of a 1070 nm microsecond laser achieved material removal from both surfaces at about 0.5 μm/μs—around 500 times faster than conventional picosecond-laser machining. Molten material and particle-like debris were ejected from the front and rear surfaces, respectively. These results demonstrate the high potential of Bessel TSL processing for ultra-high-speed sapphire micromachining.

Fog collection is receiving increasing attention for relieving the global water crisis especially in semi-arid deserts and inland areas.In the paper,we propose a simple method to prepare a superhydrophobic surface of groove-bump for efficient fog collecting.The surface has a contact angle of over 160° and obvious anisotropy. The experiment of fog water collecting shows the fog collection efficiency is high as 4000mg.cm-2.h-1,it is synergistic effect of the bump structure and groove structure.

Powder Bed Fusion (PBF) is an Additive Manufacturing technique in which a laser sinters polymer powders such as polyamide 12 (PA12). A major limitation is thermal ageing of the feedstock caused by continuous preheating, which limits material reusability. Typically, only about 10% of the powder is processed into parts, while the remainder must be refreshed with virgin material or restored through additional postprocessing techniques. Dual Beam Laser Sintering (DBLS) is an alternative approach that uses two lasers - one for preheating and one for sintering - eliminating the need for external heaters and allowing processing at room temperature. Previous works have shown that unused powder in DBLS can be directly reused in closed-loop due to minimal thermal ageing. In this work, we present a new galvoscanner-based DBLS system that enables faster sintering, in-situ temperature monitoring, and improved beam steering, supporting higher part quality and greater process sustainability.

Laser-induced graphene (LIG) is a promising material for sensing applications owing to its notable electrical properties, ease of preparation, cost-effectiveness, porous architecture, and scalable laser fabrication. This talk will present two environmental sensing applications that we have developed using LIG. Lithium detection has become increasingly important for environmental monitoring, resource extraction and recycling processes, and lithium-based therapies, among other applications. We developed an electrochemical sensor that combines LIG with manganese oxides to detect lithium ions. Manganese oxides contribute favorable ion-selective and catalytic properties owing to their variable oxidation states and versatile crystalline topologies. We compared two types of manganese oxide electrodes: one fabricated by in-situ conversion of manganese chloride during the LIG synthesis process using a laser, and the other with pre-synthesized manganese oxide particles incorporated into the LIG precursor. This talk will discuss the performance of these electrodes. The second application utilizes LIG's capacitive properties to detect and quantify particulate matter (PM), especially black carbon (BC), in the air. BC, a constituent of PM2.5, is linked to early death in humans and and can accelerate short-term warming. To develop a portable BC sensor that enables real-time, rapid detection, we integrated laser-assisted manufacturing with industrial design, resulting in a versatile, compact sensor module. This talk will discuss the fabrication method, design, and sensor performance. Through these two applications, this talk will highlight the versatility of LIG and offer a promising route to the development of high-performance, cost-effective sensors.

In this study, we demonstrate the capability of femtosecond laser surface engineering to generate precise micro- and nanostructures that fundamentally alter the wetting and optical properties of glass surfaces. By inducing spatially-selective superhydrophilicity, we achieve stable anti-fogging performance. Furthermore, the formation of laser-induced periodic surface structures (LIPSS) creates a gradient refractive index layer, delivering wideband antireflective performance. In particular, we focus on obtaining high spatial frequency LIPSS on pure glass substrates. We investigate the influence of laser parameters on the morphology and uniformity of nanostructures. We show the reflectance spectra of the laser-textured glass. We discuss the industrial scalability of this process, highlighting the necessity of stable femtosecond laser sources to ensure uniformity across large areas. This dry, contactless, and chemically free method enables scalable, spatially selective patterning and provides a sustainable strategy for anti-fog and anti-reflective glass in various applications. The results were obtained using a laser source delivering 200 μJ, <270 fs pulses at 1030 nm. (Jasper X1, Fluence Technology, Poland).

Volumetric printing by reverse tomography—commonly referred to as tomographic volumetric additive manufacturing (TVAM), or simply VAM—is a layerless 3D printing approach that creates solid objects by projecting sequences of light patterns into a rotating photosensitive resin. The cumulative energy deposition leads to localized photopolymerization, enabling the fabrication of complex 3D structures within seconds. Since its first demonstration in 2019, TVAM has rapidly gained attention and has been extended to a wide range of materials, including polymers, hydrogels, ceramics, metals, and glass. Despite these advances, several fundamental challenges remain: expanding the achievable build volume, improving resolution toward that of two-photon polymerization, and extending the method to non-transparent or composite resins. Beyond these technical hurdles, TVAM also opens unique opportunities not accessible to traditional additive manufacturing techniques—for example, the ability to fabricate directly around existing structures. This talk will review the progress of the field, highlight key developments, and explore emerging strategies to address current limitations while pointing toward new application domains.

Hollow core fibres (HCFs) guide light through a gas-filled core rather than solid glass and offer unique optical properties and transformative potential. Recent breakthroughs have reduced losses to levels below those of conventional silica fibres across a broad spectrum—from the ultraviolet to the mid-infrared. While these advances were primarily driven by applications in high-capacity data transmission, the capabilities of HCFs extend far beyond communications. They enable enhanced light–matter interactions, exceptional radiation hardness and low non-linearity for sensing applications such as gas detection and precision gyroscopes. There is even the prospect of light transmission in vacuum, pushing towards ultimate waveguide performance. As fibre designs improve, controlling the internal gas composition and pressure becomes critical, driving progress in gas dynamics modelling, advanced characterisation, and post-processing techniques. This talk will explore recent progress in HCF technology, the pivotal role of gas in transmission, and the opportunities and challenges of guiding light through a hollow core.

This presentation surveys current trends and future perspectives on how data science and AI advance photonics, with a focus on laser-based manufacturing. Fraunhofer ILT and RWTH Aachen University have successfully demonstrated solutions across AI- and data-driven laser and optical system design, process monitoring, and parameter optimization, with progress toward self-learning manufacturing systems. These approaches demonstrably improve product quality while reducing development time and production costs, highlighting the transformative potential of AI across the photonics value chain.

Optimising laser keyhole welding, a process critical for high-volume industries, is challenging due to its complex, interdependent parameters and physical phenomena. Traditional modeling and experimental optimisation are often ineffective. In this study, we evaluated machine learning models (deep learning TabPFN and a simpler Multi-Layer Perceptron) for predicting weld penetration and generating processing maps. While deep learning (R² = 0.94) and optimised MLP (R² = 0.92) excelled within training ranges, they struggled with extrapolation. Surprisingly, a basic MLP (R² = 0.87) demonstrated superior performance beyond the training data.

This work is focused on laser texturing using femtosecond lasers. Such a process enables surface treatment for functionalization purposes like coloring or modification of tribological properties or wettability. However, the laser texturing process is sensitive to changes in laser parameters, changes in the nature and material of the textured surface, and also to environmental conditions. In this work, the objective is hence to develop a monitoring strategy to help the development of the process. An instrumentation is first proposed and discussed. The process emits light signals that we propose to track with a spectrometer. The light intensity is characterized across the entire spectrum between 200 and 1100 nm. Our proposal is to use these spectral data acquired over time to train a deep learning model and then to get a prediction of process output and process conditions. Two Resnet models are trained and characterized on experimental datasets of spectro-temporal data. Datasets and models are released as open-source resources. The models are built considering two scenarios of supervision : i) monitoring texturing conditions, specifically fluence and laser spot overlap, and ii) monitoring the gray level of a generated texture. We present two deep learning models. The first achieves R² coefficients of 0.98 for fluence and 0.96 for overlap supervision. The second model estimates the gray level of the produced texture with an average accuracy of 11% of the full grayscale range. The performance of both models is also assessed using data collected with an intentionally introduced laser focus defect. The models successfully detect changes in texturing conditions, demonstrating their robustness relative to focus defects. Finally, a study is performed to identify the more relevant wavelengths in the spectral data. It shows the use of photodiodes at specific wavelengths could constitute a relevant instrumentation approach for supervision in industrial applications.

Laser microhole drilling often relies on empirical methods due to beam imperfections, complex process parameters, and limited metrology. We present a structured, data-driven approach to improve process control and repeatability. Three case studies are discussed: (i) dynamic power modulation to compensate for thermal effects during high-speed drilling with >120W ultrafast lasers, (ii) correction of hole distortion in thick ceramics using human-in-the-loop Bayesian optimisation, and (iii) predictive modelling of laser parameters by training machine learning models on historical data for “first-time-right” machining. These strategies reduce reliance on expert intuition for optimisation, improving hole size consistency and shape fidelity. Our results show that intelligent compensation can enhance the performance of imperfect laser systems, offering a cost-effective alternative to more advanced hardware.

This study examines how the quality and diversity of training data affect the performance of computer-generated holography assisted by artificial intelligence for laser beam shaping. Using the DeepCGH framework based on a convolutional neural network, we evaluate various datasets ranging from simple shapes to complex word-based patterns. The results show that diverse and heterogeneous data improve reconstruction accuracy and generalization. The work highlights the need for hybrid approaches that combine data diversity with physical modeling to achieve more stable and reliable holographic generation.

Material ablation using ultrashort-pulse lasers enables highly precise microfabrication of a wide range of materials and is widely used in the production of electronic components, mechanical parts, and medical devices. As a result, ultrashort-pulse laser processing is expected to play a key role in achieving mass customization in future manufacturing. In this study, to achieve faster and more accurate laser microfabrication, we demonstrate holographic laser processing combined with interferometric measurement of the processed structure. The measurement results are fed back into the holographic beam-shaping, enabling the fabricated structure to converge toward the desired target profile.

The non-ablative interaction of femtosecond lasers with transparent substrates gives rise to complex phenomena yielding a rich taxonomy of surface and volumetric material structural changes. Stemming from the inherent cumulative nature of the interaction, i.e. the response to each pulse depends on that of its predecessors, these phenomena remain complex to control, as the outcome results from concurrent and cascading events with diverse time constants. Here, we explore a fast method operating at 10 MHz, based on the monitoring of absorption mechanisms in the mid-infrared domain to dynamically observe laser-induced events, such as bubble nucleation, crack formation and localised melting.

Laser-induced breakdown spectroscopy (LIBS) with femtosecond pulses enables both elemental and molecular detection, allowing characterization of non-metallic materials with minimal thermal damage. We implemented fs-LIBS to analyze copper-coated Lyocell textiles with micrometer spatial selectivity. Depth-resolved single-shot spectra revealed a rapid transition from Cu emission to CN and C-C bands, enabling in-situ identification of the coating–substrate interface. Uniformly coated regions showed consistent transitions, whereas heterogeneous areas indicated variations in coating thickness and oxide structure. Results agreed with SEM/EDX (~20 µm coating). Fs-LIBS also detected trace deposition residues and oxide layers, offering a minimally destructive tool for mapping microscale coating uniformity.

An entirely optics-free technique for pulse duration estimation and monitoring is proposed. The approach relies on the generation and monitoring of an acoustic signal resulting from the air breakdown induced by focused ultrashort laser pulses. The experimentally determined dependence of the acoustic signal amplitude on pulse energy and duration is in accordance with the plasma physics of air breakdown. The proposed technique offers simplicity of implementation, compatibility with laser radiation of all spectral ranges, and suitability for in-situ monitoring of pulse duration and energy fluctuations in laser materials processing.

This work introduces a real-time, closed-loop system for detecting chemical layer transitions during femtosecond (fs) laser micromachining of multi-layer metallic substrates using Laser-Induced Breakdown Spectroscopy (LIBS). The goal is to autonomously stop the laser upon reaching a new material interface—such as aluminum (Al), copper (Cu), or stainless steel (SS)—to prevent damage to underlying layers. An integrated setup combines a high-repetition-rate fs laser with a spectrometer that continuously monitors plasma emission. Spectral data are streamed to a Python-based pipeline, where a Partial Least Squares Discriminant Analysis (PLS-DA) model instantly classifies the ablated material. Upon detecting a layer change, the system sends a stop command to the laser controller. The approach achieves reliable layer identification and process interruption within 500 ms. Results validate the integration of fs-LIBS with real-time feedback for intelligent, precision-controlled micromachining in multi-material systems.