1. School of Physics and Engineering ITMO University Saint‐Petersburg RUS–197101 Russia
2. Institute for Experimental Physics University of Hamburg Hamburg D–22761 Germany
3. Helmholtz–Institut Jena Jena D–07743 Germany
4. Theoretisch‐Physikalisches Institut Friedrich‐Schiller‐Universität Jena Jena D–07743 Germany
5. Novosibirsk State University Novosibirsk RUS–630090 Russia
6. Sobolev Institute of Mathematics Novosibirsk RUS–630090 Russia
7. Fundamental physics for metrology Physikalisch–Technische Bundesanstalt Braunschweig D–38116 Germany
8. Institut für Mathematische Physik Technische Universität Braunschweig Braunschweig D–38106 Germany
9. Laboratory for Emerging Nanometrology Braunschweig Braunschweig D‐38106 Germany