1. Polymer Institute of the Slovak Academy of Sciences; Dúbravská Cesta 9, 845 41 Bratislava Slovakia
2. Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics; Comenius University; Mlynská Dolina, 842 48 Bratislava Slovakia
3. International Laser Center; Ilkovičova 3, 841 04 Bratislava Slovakia