1. Amirkhanov Institute of Physics, Dagestan Federal Research Center, Russian Academy of Sciences, St. M. Yaragskogo 94, 367003 Makhachkala, Russia
2. Physical Department, Dagestan State University, St. M. Gadjieva 43-a, 367015 Makhachkala, Russia
3. Federal Research Centre “The Southern Scientific Centre”, Russian Academy of Sciences, 344006 Rostov-on-Don, Russia
4. Department of Physics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 2848/8, 61600 Brno, Czech Republic