Tailoring Magnetic Dipole Emission by Broken-Symmetry TiO2 Metasurfaces

Abstract

Strong magnetic dipole emission is offered by rare earth ions such as trivalent lanthanides, due to selection rule forbidden electric dipole (ED) transitions. This stimulates the study of optical nanostructures, which efficiently tailor magnetic dipole emission. High refractive index all dielectric nanostructures are promising candidates in this regard due to their strong magnetic response and negligible absorption loss in the visible spectral range. Here, we design and experimentally realize a broken-symmetry titanium dioxide (TiO2) metasurface supporting an out-of-plane magnetic dipole (MD) resonance at 590 nm wavelength, corresponding to the MD transition of trivalent Europium ions (Eu3+). A strong photoluminescence (PL) enhancement of the MD transition up to a factor of 15.5 is observed.