1. Department of Materials Science and Technology, University of Crete, 71003 Heraklion, Crete, Greece
2. Institute of Electronic Structure and Laser, Foundation for Research and Technology - Hellas, 71110 Heraklion, Crete, Greece
3. Spin Optics Laboratory, State University of Saint-Petersburg, 1 Ulianovskaya, 198504 St. Petersburg, Russia
4. Department of Physics, University of Crete, 71003 Heraklion, Crete, Greece
5. School of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, United Kingdom