1. Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi, Roma, Italy
2. Laboratoire de Physique des Lasers, Atomes et Molecules (PhLAM), UMR-CNRS 8523, CNRS, University of Lille, Lille, France
3. CNRS, Institute of Electronics Microelectronics and Nanotechnology, University of Lille, Villeneuve-d’Ascq, France