1. Experimentelle Physik 2; Technische Universität Dortmund; 44221 Dortmund Germany
2. A.F. Ioffe Physical-Technical Institute; Russian Academy of Sciences; 194021 St. Petersburg Russia
3. Spin Optics Laboratory; St. Petersburg State University; 198504 St. Petersburg Russia
4. Institute for Solid State Physics; Russian Academy of Sciences; 142432 Chernogolovka, Moscow Region Russia
5. Physico-Technical Research Institute of Nizhny Novgorod State University; 603950 Nizhny Novgorod Russia