1. a Optikzentrum NRW, Universitätsstraße 142 , D-44799 , Bochum , Germany
2. b Institute of Applied Physics Problems , Kurchatova 7, Minsk , 220064 , Rep. Belarus
3. c Military University of Technology, Institute of Chemistry , 01-489 , Warsaw 49 , Poland
4. d University of Vilnius, Liquid Crystals Lab. , 2734, Vilnius, Universiteto St. 3, Lithuania