1. Institute for Polymers, Composites and Biomaterials − National Research Council, Mostra d’oltremare Pad 20,
Viale Kennedy 54, 80125 Naples, Italy
2. SPIN − National Research Council, Complesso Universitario Monte Sant’Angelo, Via Cinthia, 80126 Naples, Italy
3. National Institute of Optics − National Research Council, Largo E. Fermi 6, 50125 Florence, Italy