1. Kotel’nikov’s Institute of Radio-Engineering and Electronics of RAS, Saratov Branch, Zelenaya 38, Saratov 410019, Russian Federation
2. Department of Nonlinear Processes, Chernyshevsky Saratov State University, Astrahkanskaya 83, Saratov 410012, Russian Federation
3. Department of Nano- and Biomedical Technology, Chernyshevsky Saratov State University, Astrakhanskaya 83, Saratov 410012, Russian Federation