1. Institute for Physical Research, National Academy of Sciences of RA, Ashtarak 0203, Armenia
2. Institute of Physics of the Czech Academy of Sciences, 16200 Prague, Czech Republic
3. Institut Lumière Matière UMR 5306 CNRS, Universite Claude Bernard Lyon 1, F-69622, Villeurbanne, France
4. Institut Universitaire de France (IUF), France