Endoscopic light delivery for ablation and 3D printing
July 23-26, 2017
Laser ablation and 3D printing are complimentary tools in manufacturing. The use of optical fibers to deliver high laser power for material ablation in confined places could open the path for a wide variety of applications (fig 1.). Similarly, the use of optical fibers capable of delivering high peak power focused pulses can be used to make 3D structures via 2 photon polymerization (2PP) in spaces difficult to access (fig 2). However, modal dispersion in multimode fibers scrambles the input wavefront, resulting in a speckle pattern at the output. By using wavefront shaping techniques to shape the light coupled into a multimode fiber, a focus spot can be created at the output. Controlling the wavefront of the input pulse allows scanning of the focus spot around the area of interest. When the peak intensity of the focus spot exceeds the threshold for ablation of the desired material, micro-pattern formation can be achieved. In order to minimize modal dispersion in the fiber, fiber modes of similar propagation constants are selectively excited. We achieved 10 mW of spatial diffraction limited focusing with 120 fs duration through a 5 cm GRIN multimode fiber. This level of peak intensity is suitable for 2PP.
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Christophe Moser, Edgar E. Morales-Delgado, Paul Delrot, Don Conkey, Damien Loterie, Nicolino Stasio, Demetri Psaltis, and Eirini Kakkava, "Endoscopic light delivery for ablation and 3D printing" in "Advances in Optics for Biotechnology, Medicine and Surgery XV", Peter So, Massachusetts Institute of Technology, USA Kate Bechtel, Triple Ring Technologies, USA Ivo Vellekoop, University of Twente, The Netherlands Michael Choma, Yale University, USA Eds, ECI Symposium Series, (2017). http://dc.engconfintl.org/biotech_med_xv/35