1. Van der Waals-Zeeman Institute, Institute of Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
2. Advanced Research Center for Nanolithography, Science Park 904, 1098 XG Amsterdam, The Netherlands
3. Department of Biomolecular Nanotechnology, MESA+ Institute, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
4. AMOLF, Science Park 904, 1098 XG Amsterdam, The Netherlands