1. Department of Molecular Biophysics and Polymer Physics, Saint-Petersburg State University, Universitetskaya nab. 7/9 , 199034 St. Petersburg, Russia
2. P.N. Lebedev Physical Institute, Russian Academy of Sciences, 53 Leninsky Pr., 119991 Moscow, Russia
3. Department of Physics, Tomsk State University, Tomsk 634050, Russia