Heidelberg 2015 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 30: Laser Development: Solid State and Semiconductor Lasers
Q 30.5: Talk
Tuesday, March 24, 2015, 15:30–15:45, K/HS2
Circularly curved waveguide lasers inscribed into Yb:YAG by direct fs-laser writing — •Thomas Calmano1,2, Lukas Terkowski1, Sven H. Waeselmann1, Christian Kränkel1,2, and Günter Huber1,2 — 1Institut für Laser-Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg — 2The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg
In this contribution we report about curved waveguide lasers, which are suitable as basic components for complex active optical devices. The waveguides consist of segments of circles with an arc length of about 15 mm and radii of curvature between 30 mm and 80 mm. The waveguiding structures were inscribed by direct fs-laser writing. This technique allows for the inscription of waveguides in three dimensions into a wide range of dielectric materials including various laser crystals. In this work we utilized ytterbium doped Y3Al5O12 (Yb:YAG) for the fs-laser inscription. Yb:YAG offers excellent thermomechanical properties and a large gain due to high peak emission cross sections. Furthermore, the low quantum defect enables highly efficient lasers. Thus, nearly 80% slope efficiency and more than 5 W of output power could be demonstrated with Yb:YAG waveguide lasers in the past. With the circularly curved waveguides presented in this work more than 40% slope efficiency for radii between 60 mm and 80 mm and more than 1.5 W of output power were achieved. However, the maximum output power and slope efficiency decreased to approximately 0.9 W and 25%, respectively, for the waveguides with smaller radii.