1. Physical Faculty; Saint Petersburg State University; 7/9 Universitetskaya nab Saint Petersburg 199034 Russia
2. Laboratory of Physics; Lappeenranta University of Technology; Box 20 53851 Lappeenranta Finland
3. Engineering and Physical Faculty; Saint Petersburg National Research University of Information Technologies, Mechanics and Optics; Kronverkskiy pr. 49 Saint Petersburg 197101 Russia