1. BioNano Systems Laboratory and Photonics Laboratory, MC2, and Department of Applied Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden, Department of Electronics, University of Barcelona, Martí i Franquès n1, 08028 Barcelona, Spain, and Interdisciplinary Nanoscience Center (iNANO), University of Aarhus, 8000 Aarhus C, Denmark