1. Department of Electrical and Computer Engineering University of Wisconsin–Madison 1415 Engineering Drive Madison WI 53705 USA
2. Department of Materials Science & Engineering University of Wisconsin–Madison Madison WI 53706 USA
3. School of Materials Engineering Purdue University West Lafayette IN 47907 USA
4. Physical Sciences Inc. 20 New England Business Center Andover MA 01810‐1077 USA
5. Institute for Solid State Physics Friedrich‐Schiller‐Universität Jena 07743 Jena Germany
6. Felix Bloch Institute for Solid State Physics Universität Leipzig Linnéstr. 5 04103 Leipzig Germany
7. ELI Beamlines/Fyzikální ústav AV ČR, v.v.i. Za Radnicí 835 25241 Dolní Břežany Czech Republic
8. Department of Physics College of William and Mary Williamsburg VA 23187‐8795 USA
9. Institut für Physik Technische Universität Ilmenau Weimarer Straße 32 98693 Ilmenau Germany