1. Institute for Solid State Physics, Friedrich Schiller University Jena, Helmholtzweg 3, 07743 Jena, Germany
2. Department of Quantum Detection, Leibniz Institute of Photonic Technology (IPHT), Albert-Einstein-Str. 9, 07745 Jena, Germany
3. Peter Grünberg Institut (PGI-7), Forschungszentrum Juelich GmbH, Wilhelm-Johnen-Str., 52428 Juelich, Germany
4. Institute of Computer Science and Computer Engineering, University of Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany