1. Department of Physics, Blackett Laboratory, Imperial College London, London SW7 2BW, United Kingdom
2. Department of Engineering, Engineering Building, Lancaster University, Bailrigg, Lancaster LA1 4YR, United Kingdom
3. Institute of Chemical Engineering and High Temperature Processes (ICEHT), Foundation of Research and Technology Hellas (FORTH), Stadiou Strasse Platani, P.O. Box 1414, Patras GR-265 04, Greece
4. Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology-Hellas (FORTH), Heraklion 71003, Greece
5. Materials Science and Technology Department, University, of Crete, Heraklion 71003, Greece
6. Laboratory of Applied Physics, Department of Physics, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece