1. Institute of Applied Physics, Abbe Center of Photonics; Friedrich-Schiller-University Jena; Albert-Einstein-Straße 15 07745 Jena Germany
2. Helmholtz Institute Jena; Fröbelstieg 3 07743 Jena Germany
3. Active Fiber Systems GmbH; Wildenbruchstraße 15 07745 Jena Germany
4. Centre Lasers Intenses et Applications; 43 rue Pierre NOAILLES 33405 Talence Cedex France
5. Fraunhofer Institute for Applied Optics and Precision Engineering; Albert-Einstein-Straße 7 07745 Jena Germany