1. Advanced
Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
2. Department
of Physics and Astronomy, Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus C, Denmark
3. SUPA,
School of Physics and Astronomy, University of St. Andrews, St. Andrews KY16 9AJ, United Kingdom
4. Institute
of Condensed Matter Physics, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
5. Central
Laser Facility, STFC Rutherford Appleton Laboratory, Harwell OX11 0QX, United Kingdom