1. Institute of Physics of NAS of Ukraine, Kyiv, Ukraine;
2. Institute of Applied Physics, Johannes Kepler University Linz, Linz, Austria;
3. Bionanophotonics, Department of Physics, Chalmers University of Technology, Gothenburg, Sweden;
4. School of Physics and CRANN, Trinity College Dublin, College Green, Dublin 2, Ireland;
5. IIT Graphene Labs, Istituto Italiano di Tecnologia, Genova, Italy