Address : Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete, Greece. \\ Electrical Engineering Department, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete, Greece. \\ Institute of Electronic Structure and Laser, Foundation for Research & Technology- Hellas, P.O. Box 1527, Vassilika Vouton, 711 10 Heraklion, Crete, Greece |