1. Department of Physics, NLHT-Lab, University of Calabria and CNR-NANOTEC, Institute of Nanotechnology, 87036 Rende, Italy
2. Institute of Applied Sciences and Intelligent Systems “E. Caianiello” CNR, 80078 Pozzuoli, Italy
3. Department of Physics, Integrated Science Lab and Umeå Centre for Microbial Research, Umeå University, 901 87 Umeå, Sweden
4. Department of Physics, Case Western Reserve University, 2076 Adelbert Rd, Cleveland, Ohio 44106, United States