1. Research Institute for Nuclear Problems Belarusian State University, Minsk 220030, Belarus
2. Center for Physical Sciences and Technology, Sauletekio av. 3, LT-10257 Vilnius, Lithuania
3. Faculty of Physics, Vilnius University, Sauletekio av. 3, LT-10257 Vilnius, Lithuania
4. Institute of Photonics, Department of Physics and Mathematics, University of Eastern Finland, Yliopistokatu 7, FI-80101 Joensuu, Finland