1. Institute of Electronic Structure and Laser, FORTH, 70013 Heraklion, Crete, Greece
2. Department of Materials Science and Technology, University of Crete, 70013 Heraklion, Crete, Greece
3. Institute for Nuclear Problems, Belarusian State University, Bobruiskaya 11, 220030 Minsk, Belarus
4. Tomsk State University, 36 Lenin Avenue, Tomsk 634050, Russia
5. Science Program, Texas A&M University at Qatar, P.O. Box 23874, Doha, Qatar
6. Department of Physics, University of Crete, 70013 Heraklion, Crete, Greece
7. Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, United States