1. I3N and Physics Department University of Aveiro Campus of Santiago 3810-193 Aveiro Portugal
2. Institute of Physics of Advanced Materials Nanotechnology and Nanophotonics Department of Physics and Astronomy University of Porto Rua do Campo Alegre, 687 4169-007 Porto Portugal
3. CICECO-Aveiro Institute of Materials and Physics Department University of Aveiro Campus of Santiago 3810-193 Aveiro Portugal
4. College of Engineering Shibaura Institute of Technology 3-7-5 Toyosu, Koto-ku Tokyo 135-8548 Japan
5. Institute of Innovative Research Tokyo Institute of Technology 4259 Nagatsuta-cho Midori-ku Yokohama 226-8503 Japan
6. Faculty of Engineering Yokohama National University 79-5 Tokiwadai Hodogaya-ku Yokohama 240-8501 Japan
7. Instituto de Telecomunicações and Department of Electrical and Computer Engineering University of Lisbon Av. Rovisco Pais, n.1 1000-049 Lisboa Portugal