1. Institute of Physical Engineering Faculty of Mechanical Engineering Brno University of Technology Technická 2 Brno 61669 Czech Republic
2. Central European Institute of Technology Brno University of Technology Purkyňova 656/123 Brno 61200 Czech Republic
3. Department of Optics Palacký University 17. listopadu 1192/12 Olomouc 77146 Czech Republic