11:15am - 11:30am
Molded parts with functional surfaces – how laser microstructuring can be used for low-cost mass products
Laser Zentrum Hannover e.V., Germany
Microstructuring via ultrashort pulse laser enables the targeted generation of functional surface structures. With this technology, progress in material behavior has been shown in tribological, optical and haptical properties, liquid wettability and cell adhesion. In cases where the effect is mainly based on the laser-generated microstructures instead of laser-induced chemical changes of the surface material, injection molding offers a possibility to make the usually high-priced laser surface functionalization accessible to low-cost mass products. This technique leaves the chemistry of the molded parts unaffected, which makes it especially attractive for biomedical applications. Molding inverts the surface topography and can be associated with resolution, durability and demoldability restrictions. We present our current results and findings on basic as well as on application-oriented issues. Selected applications including a technique for piracy protection are discussed.
11:30am - 11:45am
Towards optimization of femtosecond laser pulse nano-structuring for high-intensity laser interactions
1Institut für Laser und Optik, Hochschule Emden/Leer – University of Applied Sciences, Constantiaplatz 4, 26723 Emden, Germany; 2Sankt Petersburg State University, Sankt Petersburg, Russia; 3Institut für Physik, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstr. 114-118, 26111 Oldenburg, Germany
The interaction of intense femtosecond laser pulses with solid targets is a topic that has attracted large interest in science and applications. For many of the related experiments a large energy deposition or absorption and an efficient coupling to XUV- and/or X-ray photons and/or high energy particles is important. Here, beside improvements in laser pulse properties also those of the target are relevant. The present work investigates the formation of laser-induced periodic surface structures on massive metal targets by femtosecond laser pulses in vacuum. The experimental results and the ripple formation mechanisms have been analysed and interpreted with newly developed theoretical models. The present results contribute to a simple optimization of targets by nano-structuring their surface in-situ which leads to a significantly enhanced absorption and conversion efficiency into XUV emission, X-rays and/or high energy electrons and protons after irradiation with a subsequent intense laser pulse.
11:45am - 12:00pm
Targeting mass production of nano/micro textured surfaces by USP laser: the New Skin project
Alphanov, Aquitaine Institute of Optic - Rue F. Mitterand 33400 Talence (France)
Ultra-Short Pulse laser texturing (USP-LT) is a key technology for functionalisation of materials surface. Although the texturing of ≈1m2 surfaces have been successfully shown, extend USP-LT over several m2 surfaces represents an issue due to the need of high P, and a difficult process control. The “New Skin” project could represent a turning point pushing the readiness of USP-LT with a significant up-scale of the production volume.
Here we show the preliminary results obtained with the implementation of a demonstrative pilot line based on a 350 W, fs laser and a polygon scanner. We report the optimisation of the structures morphology on steel when P exceeds few hundreds of watts as well as the impact of the repetition rate (up to 10 MHz) and the hatch. A roll-to-roll approach is proposed jointly with an in-line monitoring system based on scatterometry. Finally, possible applications and values propositions are introduced and discussed.
12:00pm - 12:15pm
In-line monitoring of submicron laser texturing: a test bench for scatterometry
Laser Induced Periodic Surface Structures (LIPSSs) with a submicronic periodicity induce a variety of surface properties (iridescence, hydrophobicity, antibacterial, etc.). In-line monitoring of LIPSS dimensions is challenging since the resolution of optical based microscopy techniques is insufficient or unable to withstand with harsh, industrial environment. These issues can be overcome using indirect measurement techniques such as scatterometry. It makes possible an indirect measurement of LIPSS morphology by analysing the reflection and/or diffraction pattern of an incoming light having a known spectrum and polarisation. We show that by using a proper configuration, scatterometry is barely sensitive to vibrations and fast enough for in-line monitoring fitting industrial requirements. In the frame of the NewSkin H2020 project, a scatterometer has been integrated and tested in a roll-to-roll machine including a fast polygon scanner (up to 200 m/s) and a 350 W femtosecond laser targeting mass production of LIPSS for antibacterial stainless steel.
12:15pm - 12:30pm
Effects of various misalignments and beam impurities on creation of optical needle using Pancharatnam-Berry phase elements
1Center for Physical Sciences and Technology, Vilnius University, Lithuania; 2Vilnius Gediminas Technical University, Faculty of Electronics, Lithuania; 3Workshop of Photonics