The microfluidics field, due to its various possibilities in the study of chemical and biological reactions with only few consumables, is expanding significantly. A flexible solution has been developed based on Ultra-Short Pulsed laser technology to engrave different microfluidic channels on a chip, and to seal them. We describe here a solution to improve the welding’s speed and quality based on a tailored beam shaping with Multi-Plane Light Conversion (MPLC) technology. The fully reflective module is used with a high-power femtosecond laser. The optical performance of the module and achieved improvement on the welding are detailed.

The scope of utilizing soft materials is expanding further in recent years because of the flexibility and the good biocompatibility. In this presentation, laser direct writing of microstructures that exhibits optical and/or electrical properties in and on soft materials by means of photoreduction and graphitization will be described. The fabrication of metal microstructures by multi-photon photoreduction within PEGDA and pNIPAM hydrogels will be reviewed in addition to recent results on applications toward soft actuators. Femtosecond laser direct writing of highly crystalline graphene from native PDMS as well as cellulose nanofiber films, a sustainable biomass, and its application for a highly sensitive piezoresistive sensor will also be presented.

The seamless integration of customized micro-optical components into light-sensitive devices remains a challenging task toward enhancing the performance of solar cells and photodetectors. In this talk, I will show how laser additive processes can help ease this problem. We use laser pulses for depositing microdroplets and microdisks at targeted positions on a substrate. Following a photocuring or thermal reflow process, these elements are converted into microlenses and microlens arrays whose geometry, size, and optical properties solely depend on the laser parameters and substrate used. The excellent optical quality of the so-fabricated micro-optics offers a promising route for next-generation optoelectronic systems.

One important parameter that is often not considered in the formation of laser-induced periodic surface structures (LIPSS) is the laser-induced oxidation produced when oxidation prone materials are irradiated in air environment. In this work, we characterize the response of the oxidation prone hard-coating material chromium nitride and explain the findings with finite-difference time-domain calculations. We also employ complementary surface and in-depth analytic techniques to reveal morphological, chemical and structural features of different types of surface structures and LIPSS produced on titanium-based substrates.

Laser Induced Forward Transfer (LIFT) associated with ultrashort laser pulses enables high-resolution depositions while avoiding the transferred material degradation. In this work, Platinum thin films were used as donor material for fs-LIFT, employing a fs-laser centered at 1030 nm as the excitation source. The deposition characteristics and the incubation effect were studied. It was observed that the depositions get homogeneous and well-defined for pulse energies on the order of 6 µJ.

Laser-induced near-field effect concentrates the laser energy to be enhanced on a localized area much smaller than the wavelength for nanoprocessing. Owing to the superhigh fabrication resolution, the laser near-field processing has been used for the surface nanostructuring to create photonic devices. The near-field processing is typically performed by using scanning optical microscope or scanning probe microscope combined with laser, while nano/microspheres provide the unique advantages of maskless, time-saving schemes. In this paper, laser near-field reduction of metal ions assisted by silica spheres is presented for fabrication of plasmonic superlattices on silicon substrate, which can tune localized surface plasmonic resonance wavelengths from the visible to the near-infrared region by adjustment of the lattice periods. In the laser near-field reduction, the incident laser is tightly focused at the bottom side of the silica sphere to confine the reaction the in near-field.

Controlling the electrical properties as desired is a key technology for high-performance functional electronics. Some transition metals have been found in multiple oxidation states in nature, showing distinctive characteristics with multiple bandgap state from the same material. Active electronics are usually composed of a semiconductor and metal electrodes which are connected by multiple vacuum deposition steps and photolithography patterning. However, the presence of interface of dissimilar material between a semiconductor and a metal electrode makes various problems in electrical contacts and mechanical failure. The ideal electronics should not have problematic interfaces of dissimilar materials. In this study, we developed a novel method to fabricate active electronic components in a monolithic seamless fashion where both metal and semiconductor can be prepared from the same monolith material without creating semiconductor-metal interface.

In this contribution we focus on micro-machining of several materials in different processing regimes. The temporal energy deposition is influenced during operation on a femto- up to a microsecond timescale. Using an off-axis microscope, we present camera image sequences automatically obtained during the ablation process, capturing the surface changes during machining, and revealing spatially and temporally resolved developments. This aids in further process understanding such as parameter dependencies and critical process regimes (formation of unwanted surface morphologies). To optimize both productivity and quality, combined processes with successive parameter sequences are demonstrated, enabled by fast and controlled intra-process pulse parameter switching.

Current trend of the average laser power increase follows Moore's law. The average power of ultra-short lasers in 2000 was 1 W and now is 1 kW following trend of doubling per year: 2^(20years/2) = 1024. This trend can be harnessed for large area patterning. Here we show application of direct laser writing for processing of surface of solar cells. Light trapping photonic crystal (PhC) patterns on the surface of Si solar cells provides a novel opportunity to approach the theoretical efficiency limit of 32.3% for light-to-electrical power conversion with a single junction cell. This is beyond the efficiency limit implied by the Lambertian limit of ray trapping ~29%. The interference and slow light effects are harnessed for collecting light even at the long wavelengths near the Si band-gap. We compare two different methods for surface patterning, that can be extended to large area surface patterning: 1) laser direct write and 2) step-&-repeat 5-times reduction projection lithography.

We report a high-performance flexible in-plane micro-supercapacitor (MSC) consisting of a graphene/laser-induced graphene hybrid film which was prepared on both sides of a polyimide (PI) film with slit-shaped through holes. The front and back side carbon electrodes were electrochemically connected by through holes filled with a polymer electrolyte. Such an in-plane MSC was prepared by laser annealing and ablation of a graphene/polyamide hybrid coating on a PI film, where the laser annealing of a hybrid coating film was conducted by a CW 445 nm diode laser and slit-shaped through holes were prepared by laser ablation using a pulse fiber laser.

Nowadays, requirements in lithium-ion battery technology tend to a contemporaneous characteristic of high energy and high power density, which presume a Pareto optimum in each step of layout design. One approach that could cover the demands of simultaneously high energy and power density regulations is the use of the so-called 3D battery concept, which enables short lithium-ion diffusion pathways and a reduced cell impedance. In this study, commercial lithium-iron-phosphate (LFP) and tape-casted lithium-nickel-manganese-cobalt-oxide (NMC) cathodes were investigated regarding degradation processes during fast discharging conditions. The visualization of such discovered regions were determined in unstructured and laser-structured electrodes by applying laser-induced breakdown spectroscopy (LIBS). Post mortem LIBS analyses of laser structured and unstructured LFP and NMC electrodes were correlated with electrochemical data offering new perspectives in studying degradation processes.

The development of ultrashort pulsed laser systems actually goes far beyond the kW level. But e.g. for metals and single pulses todays standard methods like galvo scanners are not suited for higher average powers and alternative approaches have to be developed. We will get an insight into actual developments using multi-pulse strategies in temporal representation as pulse bursts and in spatial representation as multi-beams or with direct beam forming. A combination of these methods with synchronized scanning or real pulse on demand option could pave the way for using high average powers.

Optical trapping provides a non-contact method for the three-dimensional (3D) manipulation of diverse objects. The optical positioning and linking (OPAL) platform used in this study uses an optical trap for object manipulation and a biochemical linking mechanism for building up extended 3D structures. Here we demonstrate the feasibility of the OPAL platform for the fabrication of several large-scale 3D assemblies consisting of hundreds of building blocks. We develop an efficient computer-controlled platform and explore the optimal parameters for the biochemical linking mechanism. Finally, we discuss future applications of the OPAL platform and its viability for nanostructure fabrication.

Medical implants are frequently used to replace damaged organs, structures and tissues in human body. It is essential to ensure a perfect implantation hence paramount to optimize surface topography of the implants for desired integration. For dental implants, this implies reducing bacteria settlement near the prosthesis and increasing roughness to improve implant-bone interaction and thus osseointegration. For other types of implants like bone fracture fixtures and cardiac pacemakers, reduced infection and adhesion (scar tissue) are highly desirable. Ultrafast laser is a powerful tool for modifying medical implant surfaces, at the micro- and/or nano-scale, towards improving or limiting their cell adhesions.