1. Institute of Electronics, AGH University of Science and Technology, 30-059 Kraków, Poland
2. Faculty of Physics, Warsaw University of Technology, 00-662 Warsaw, Poland
3. Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, 30-059 Kraków, Poland
4. Institute for Theoretical Physics, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
5. Institute of Molecular Physics, Polish Academy of Sciences, ul. M. Smoluchowskiego 17, 60-179 Poznań, Poland
6. Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB,
Bellaterra, 08193 Barcelona, Spain