Department of Physics, M.V. Lomonosov Moscow State University, Leninskie Gory, 1, Moscow 119991, Russia and A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilova Street, 38, Moscow 119991, Russia
Prof. Dr. Sergei G. Tikhodeev
Department of Physics, M.V. Lomonosov Moscow State University, Leninskie Gory, 1, Moscow 119991, Russia and A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Vavilova Street, 38, Moscow 119991, Russia