Vaskin, AleksandrMashhadi, S.Steinert, MichaelChong, Katie E.Keene, David W.Nanz, StefanAbass, Aimi K.Rusak, EvgeniaChoi, Duk-YongFernandez-Corbaton, IvanPertsch, ThomasRockstuhl, CarstenNoginov, MikhailKivshar, YuriNeshev, DragomirNoginova, NataliaStaude, Isabelle2020-04-011530-6984http://hdl.handle.net/1885/202560Mie-resonant high-index dielectric nanoparticles and metasurfaces have been suggested as a viable platform for enhancing both electric and magnetic dipole transitions of fluorescent emitters. While the enhancement of the electric dipole transitions by such dielectric nanoparticles has been demonstrated experimentally, the case of magnetic-dipole transitions remains largely unexplored. Here, we study the enhancement of spontaneous emission of Eu3+ ions, featuring both electric and magnetic-dominated dipole transitions, by dielectric metasurfaces composed of Mie-resonant silicon nanocylinders. By coating the metasurfaces with a layer of an Eu3+ doped polymer, we observe an enhancement of the Eu3+ emission associated with the electric (at 610 nm) and magnetic-dominated (at 590 nm) dipole transitions. The enhancement factor depends systematically on the spectral proximity of the atomic transitions to the Mie resonances as well as their multipolar order, both controlled by the nanocylinder size. Importantly, the branching ratio of emission via the electric or magnetic transition channel can be modified by carefully designing the metasurface, where the magnetic dipole transition is enhanced more than the electric transition for cylinders with radii of about 130 nm. We confirm our observations by numerical simulations based on the reciprocity principle. Our results open new opportunities for bright nanoscale light sources based on magnetic transitions.Financial support by the Thuringian State Government within its ProExcellence initiative (ACP2020) and the German Research Foundation (STA 1426/2-1) is gratefully acknowledged. K.E.C., D.N.N., and Y.S.K. acknowledge the support by the Australian Research Council (DP150103733). Y.S.K. acknowledges a support from the Alexander von Humboldt Foundation. S.N. acknowledges financial support by the Karlsruhe School of Optics and Photonics and by the DFG Priority Programm 1839 Tailored Disorder. The authors also acknowledge their participation in the Erasmus Mundus NANOPHI project, contract number 2013 5659/002- 001. N.N., M.A.N., and S.M. would like to acknowledge the support by NSF EiR grant # 1830886.application/pdfen-AU© 2019 American Chemical Society201910.1021/acs.nanolett.8b042682019-11-25