1. INRiM, Italy's National Metrology Institute, Torino, Italy
2. ISASI-CNR, Institute of Applied Sciences and Intelligent Systems, Pozzuoli (Naples), Italy
3. Leibniz Institute of Photonic Technology, Jena, Germany
4. Ruhr-University Bochum, Bochum, Germany
5. DMF-Dipartimento di Matematica e Fisica Università della Campania “L. Vanvitelli”, Caserta, Italy
6. CNR-SPIN, Institute for Superconductivity, Innovative Materials and Devices, Pozzuoli, Italy