1. Nanotechnology Department, Laser Zentrum Hannover e.V., 30419, Hannover, Germany
2. Institute of Electronic Structure and Laser (IESL), Foundation for Research and Technology Hellas (FORTH)
3. Optical Sensors Laboratory/National Centre for Sensor Research, Dublin City University
4. Department of Physics, University of Crete
5. Department of Materials Science and Technology, University of Crete