1. Department of Optics, Palacký University, 17. listopadu 12, 771 46 Olomouc, Czech Republic
2. Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic
3. Institut für Experimentalphysik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria