1. Department of Nanophotonics
and Metamaterials, ITMO University, St. Petersburg 197101, Russia
2. Nanotechnology Department, Laser Zentrum Hannover e.V., Hannover D-30419, Germany
3. Laboratory
of Chemical Thermodynamics, Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412, Russia
4. Moscow Institute of Physics and Technology, Moscow 141701 Russia
5. St. Petersburg State University, St. Petersburg 199034, Russia
6. Nonlinear
Physics Centre, Australian National University, Canberra ACT 2601, Australia