1. From the IRCCS (Istituto Ricerca e Cura a Carattere Scientifico) G. B. Bietti, Rome, Italy;
2. CNR-IPCF (Consiglio Nazionale delle Richerche-Instituto per i Processi Chimico-Fisici) Unit of Cosenza, Liquid Crystal Laboratory (LiCryL), Rende, Italy; 3Vision Engineering, Rome, Italy; and
3. the Department of Physics, University of Calabria, Rende, Italy.
4. CNR-IPCF (Consiglio Nazionale delle Richerche-Instituto per i Processi Chimico-Fisici) Unit of Cosenza, Liquid Crystal Laboratory (LiCryL), Rende, Italy; the 4Department of Physics, University of Calabria, Rende, Italy.