Bonn 2025 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 49: Poster – Photonics, Lasers, and Applications
Q 49.19: Poster
Wednesday, March 12, 2025, 17:00–19:00, Tent
Using Rh6G as sensitizer in commercial photoresins for two-step-absorption lithography — •Sabrina Hammel1, Georg von Freymann1,2, and Christina Jörg1 — 1Physics Department and Research Center OPTIMAS RPTU Kaiserslautern-Landau, Kaiserslautern, Deutschland — 2Fraunhofer Institute for Industrial Mathematics ITWM, Kaiserslautern, Germany
A widely used technique for creating arbitrary 3D structures at the micron scale is Direct Laser Writing (DLW), which uses the nonlinear process of Two-Photon Absorption (2PA). In 2PA, the simultaneous absorption of two photons excites a photoinitiator molecule, triggering a polymerization reaction. A recently shown technique, Two-Step-Absorption (TSA) [1], achieves similar resolution to 2PA, but needs only a simple cw-laser diode instead of a pulsed fs-laser. In TSA, the virtual state in 2PA is replaced by a real electronic state with a relatively long lifetime. So far, TSA lithography typically requires special photoresins consisting of appropriately chosen photoinitiators, scavengers and monomers. To also make commercial photoresins usable for TSA, we examine the use of a photosensitizer [2], Rhodamine 6G (Rh6G). Rh6G undergoes the TSA process, subsequently transferring energy to the photoinitiator in the commercial resin. By incorporating photosensitizers, we aim to make TSA more versatile, using existing commercial materials with minimal modification.
[1] V. Hahn, T. Messer, N.M. Bojanowski et al., Nat. Photon. 15, 932-938 (2021).
[2] D.T. Meiers et al., Adv. Eng. Mater. 25:2370037 (2023).
Keywords: direct laser writing; two-step absorption; sensitizer; micro-structures