1. ICFO – Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona, Spain
2. Center for Magneto-Optical Research Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow, Poland
3. ICREA – Institució Catalana de Recerca i Estudis Avançats, 08015 Barcelona, Spain