1. Faculty of Electronics and Telecommunications, Poznań University of Technology, Piotrowo 3A, 60-965 Poznań, Poland
2. Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland
3. Institute of Physics, Poznań University of Technology, Nieszawska 13A, 60-965 Poznań, Poland