KU Leuven, Department of Chemistry, Division for Molecular Imaging and Photonics, Laboratory for Photochemistry and Spectroscopy, Celestijnenlaan 200F, B-3001 Leuven, Belgium; Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre, Biomedical Research Institute, Agoralaan C (BIOMED), Hasselt University, B-3590 Diepenbeek, Belgium. Electronic address: jelle.hendrix@uhasselt.be.