1. Ultrafast and Nonlinear Optics LabLight and Matter Physics GroupRaman Research Institute Bangalore 560080 India
2. CIC nanoGUNETolosa Hiribidea 76 E‐20018 Donostia‐San Sebastian Spain
3. Catalan Institute of Nanoscience and Nanotechnology (ICN2)CSIC and The Barcelona Institute of Science and TechnologyCampus UAB Bellaterra 08193 Barcelona Spain
4. Institució Catalana de Recerca i Estudis Avançats (ICREA) Barcelona 08010 Barcelona Spain
5. Sagamihara Surface Laboratory SIC3, 1880‐2, Kamimizo Chuo‐ku Sagamihara Kanagawa 252‐0243 Japan