1. Photonics Laboratory, ETH Zürich, 8093 Zürich, Switzerland
2. Materials Metrology Division, Instituto Nacional de Metrologia Qualidade e Tecnologia (INMETRO), 25250-020 Duque de Caxias, Rio de Janeiro, Brazil
3. State Key Laboratory of Optoelectronic Materials and Technologies, Nanotechnology Research Center, Guangzhou Key Laboratory of Flexible Electronic Materials and Wearable Devices, School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, P.R. China
4. Faculty of Physics, Universität Wien, 1090 Wien, Austria