1. Institute of Solid State Physics , University of Latvia , 8 Kengaraga Str., LV1063 , Riga , Latvia
2. Peter the Great St.Petersburg State Polytechnic University , 29 Polytekhnicheskaya Str., 195251 , Saint-Petersburg , Russia
3. Scientific and Production Association S.I.Vavilov State Optical Institute 36 Babushkina Str., 192171 , Saint-Petersburg , Russia