1. Univ. Grenoble Alpes, F-38000 Grenoble, France
2. CEA, INAC-SP2M, “Nanophysique et Semiconducteurs” Group, F-38000 Grenoble, France
3. DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, Building 343, DK-2800 Kongens Lyngby, Denmark
4. Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland
5. CNRS, Institut Néel, “Nanophysique et Semiconducteurs” Group, F-38000 Grenoble, France