1. Max-Planck-Institut für Quantenoptik, 85748 Garching, Germany.
2. Munich Center for Quantum Science and Technology, 80799 München, Germany.
3. Department of Physics and Institute for Advanced Study, Technical University of Munich, 85748 Garching, Germany.
4. Department of Physics, Harvard University, Cambridge, MA 02138, USA.
5. Department of Physics and Astronomy, Clemson University, Clemson, SC 29631, USA.
6. Fakultät für Physik, Ludwig-Maximilians-Universität, 80799 München, Germany.
7. Institut für Laserphysik, Universität Hamburg, 22761 Hamburg, Germany.
8. The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, 22761 Hamburg, Germany.
9. Physikalisches Institut, Eberhard Karls Universität Tübingen, 72076 Tübingen, Germany.