1. National Institute for Research and Development in Microtechnologies (IMT-Bucharest), Voluntari, Ilfov, Romania
2. Physics Faculty, University of Bucharest, Bucharest, Romania
3. Department of Science and Engineering of Matter, Environment and Urban Planning, Polytechnic University of Marche, Ancona, Italy
4. Department of Information Engineering, Polytechnic University of Marche, Ancona, Italy