1. Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), 70013 Heraklion, Crete, Greece
2. Department of Materials Science and Technology, University of Crete, 70013 Heraklion, Crete, Greece
3. Department of Physics, University of Crete, 70013 Heraklion, Crete, Greece
4. Science Program, Texas A&M University at Qatar, P.O. Box 23874, 23874 Doha, Qatar