1. Université Clermont Auvergne, CNRS, SIGMA Clermont, Institut Pascal, F-63000 Clermont-Ferrand, France
2. ITMO University, Kronverkskiy pr. 49, 197101 St. Petersburg, Russia
3. Aix Marseille Univ., CNRS, CINAM, 13288 Marseille, Cedex 9, France
4. Department of Engineering Physics, McMaster University, Hamilton, Ontario L8S4L7, Canada