1. Faculty of Civil Engineering, Department of physics, Brno University of Technology, Žižkova 17, 602 00 Brno, Czech Republic
2. Faculty of Electrical Engineering and Communication, Department of Electrotechnology, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic
3. Department of Physics AVČR, Cukrovarnická 10, 162 53 Praha 6, Czech Republic