1. Physics and Chemistry of Nanostructures, Ghent University, 9000 Ghent, Belgium
2. Center for Nano and Biophotonics, Ghent University, 9000 Ghent, Belgium
3. Department of Chemical Sciences and Bernal Institute, University of Limerick, Limerick V94 T9PX, Ireland
4. Raman Spectroscopy Research Group, Department of Chemistry, Ghent University, 9000 Ghent, Belgium
5. Archaeometry Research Group, Department of Archaeology, Ghent University, 9000 Ghent, Belgium