Beckmann, DennisDennisBeckmannSchnitzler, DanielDanielSchnitzlerSchäfer, DagmarDagmarSchäferGottmann, JensJensGottmannKelbassa, IngomarIngomarKelbassa2022-05-052022-05-052011-11-28Optics Express 19 (25): 25418-25425 (2011-12-05)http://hdl.handle.net/11420/12467Waveguides with arbitrary cross sections are written in the volume of Al2O3-crystals using tightly focused femtosecond laser radiation. Utilizing a scanning system with large numerical aperture, complex cladding geometries are realized with a precision around 0.5 μm and a scanning speed up to 100 mm/s. Individual beam and mode shaping of laser diode radiation is demonstrated by varying the design of the waveguide cladding. The influence of the writing parameters on the waveguide properties are investigated resulting in a numerical aperture of the waveguides in the range of 0.1. This direct laser writing technique enables optical devices which could possibly replace bulky beam shaping setups with an integrated solution. © 2011 Optical Society of America.en1094-40872011252541825425OpticaPhysikJournal Article10.1364/OE.19.02541822273933Journal Article