1. Molecular Engineering Laboratory, Department of Physics, University of Patras, Patras 26500, GR, Greece
2. Institute of Electronic Structure and Laser, Foundation for Research &Technology Hellas, Vassilika Vouton, P.O. Box 1385, Heraklion, Crete GR 71110, Greece
3. Department of Physics, University of Cyprus, 1, Panepistimiou, street, 2109 Aglantzia, Nicosia, Cyprus