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Please note that all times are shown in the time zone of the conference. The current conference time is: 30th Apr 2025, 11:49:34pm CEST
Session Chair: Jens Bliedtner, Ernst-Abbe-Uiversity of Applied Sciences Jena, Germany
Location:A.1.7
Presentations
8:45am - 9:15am Invited ID: 389 / TOM3 S5: 1 TOM 3 Optical System Design, Tolerancing and Manufacturing
Invited - High Order Surface Artifacts on Aspheres and their Interpretation in Metrology and Tolerancing
Matthias Knobl1, Jessica DeGroote Nelson2, Michael Schneider1
1Edmund Optics GmbH, Germany; 2Edmund Optics Inc., USA
Specific surface artifacts and manufacturing errors on aspheric lenses can be interpreted in different ways based on the used metrology system. We will study one example that shows ambiguity between form error and inner centration. The investigation includes common tolerancing methods in optical design and how they can cover the observed artifacts, as well as the effects the artifacts have on optical performance.
9:15am - 9:30am ID: 103 / TOM3 S5: 2 TOM 3 Optical System Design, Tolerancing and Manufacturing
The pea puffer aspheres: circumference optimized aspheres ccp polishing
Oliver Faehnle1, Matt Balkonis2, Jessica DeGrote Nelson2
1OST – Ostschweizer Fachhochschule, Switzerland; 2Edmund Optics, USA
A noval concept for ccp polishing calles pp (pea puffer) of small diameter aspheres, typically << 5 mm, enables the generation of aspheres featuring shallow radii of curvatures while requiring clear apertures that are too small for most ccp polishing method's footprint diameters. The pea puffer concept enables a high quality and low cost manufacture of small aspheres in industry.
9:30am - 9:45am ID: 139 / TOM3 S5: 3 TOM 3 Optical System Design, Tolerancing and Manufacturing
SwissVAMyKnife.jl: an open-source package for tomographic volumetric additive manufacturing
Felix Wechsler, Carlo Gigli, Jorge Madrid-Wolff, Christophe Moser
Laboratory of Applied Photonics Devices, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
We introduce an optimization framework for ray and wave optical tomographic volumetric additive manufacturing (TVAM).
In TVAM, tomographic patterns are projected with a light modulator onto a photocurable resin from different angular directions.
Once an energy dose threshold is crossed, the resin starts polymerizing.
Current approaches assume a ray optical model for light propagation, using the Radon transform as backbone, which breaks down for small features in the region of \SI{20}{\micro\meter}.
In this work we describe how a wave optical framework allows to optically print smaller feature sizes.
The optimization framework is written in the programming language Julia and allows for high-performance optimization of ray or wave optical based patterns for volumetric additive manufacturing.
9:45am - 10:00am ID: 105 / TOM3 S5: 4 TOM 3 Optical System Design, Tolerancing and Manufacturing
Twyman effect in laser polishing
Sven Lämmler, David Bischof, Oliver Fähnle
Fachhochschule Ostschweiz - Buchs, Switzerland
This study provides a comprehensive overview of the investigation into reducing wafer deformation during laser polishing of fused silica. The study focuses on the Twyman effect, which causes unwanted curvature in thin plates subjected to surface treatment. Through careful analysis and experimentation, a strategy for minimising stress-induced deformation is proposed.
10:00am - 10:15am ID: 137 / TOM3 S5: 5 TOM 3 Optical System Design, Tolerancing and Manufacturing
Accelerating two-photon polymerization via single-photon absorption assistance
Buse Unlu1, Maria Isabel Álvarez-Castaño1, Antoine Boniface1,2, Ye Pu1, Christophe Moser1
1Laboratory of Applied Photonics Devices, School of Engineering, Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland; 2AMS Osram, Martigny, Switzerland
Photopolymerization is a light-based additive manufacturing (AM) technique that facilitates the fabrication of complex three-dimensional (3D) structures quickly and cost-effectively. One-photon polymerization allows printing with high speed despite its limited resolution. In contrast, two-photon polymerization (2PP) offers high precision and resolution but requires longer printing times. We propose a method combining 2PP and one-photon absorption (1PA) to get advantages of the dual capabilities, allowing for faster printing while preserving high resolution and enhancing depth sectioning. In this study, we employ a blue light to pre-excite a photocurable resin for rapidly reaching the polymerization threshold by 1PA and a precisely focused femtosecond beam to provide the missing energy for surpassing the threshold and solidifying the resin through two-photon absorption. First, we investigate the impact of the pre-sensitization by a blue light illumination on 2PP, demonstrating two orders of magnitude reduction in light dose. After that, we introduce a custom 3D printer utilizing blue light sensitization in a light-sheet mode on 2PP, which accelerates polymerization onset and improves surface quality.
