1. Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
2. Institute of Nanostructure Technologies and Analytics, Technische Physik, CINSaT, University of Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany
3. National Institute for Research and Development in Microtechnologies, Erou Iancu Nicolae 126A, 077190, Voluntari, Romania