1. DTU Fotonik , Technical University of Denmark , Kongens Lyngby DK-2800 , Denmark
2. Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology , Wrocław University of Science and Technology , Wybrzeże Wyspiańskiego 27 , 50-370 Wrocław , Poland
3. DTU Nanolab-National Centre for Nano Fabrication and Characterization , Technical University of Denmark , Kongens Lyngby DK-2800 , Denmark
4. NanoPhoton-Center for Nanophotonics , Technical University of Denmark , DK-2800 Kongens Lyngby , Denmark
5. Department of Theoretical Physics, Faculty of Fundamental Problems of Technology , Wrocław University of Science and Technology , 50-370 Wrocław , Poland
6. Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń , ul. Grudziądzka 5 , Toruń 87-100 , Poland
7. Faculty of Physics , St. Petersburg State University , Universitetskaya Embankment 13B , 199034 , St. Petersburg , Russia