Enhancing magnetic dipole emission with a hollow hybrid metal-dielectric-metal nanostructure

We propose hollow metal-dielectric-metal hybridized nanodisks to enhance both the magnetic dipole (MD) and electric dipole (ED) emissions. By employing a hollow hole in the center of the hybridized nanodisks, the maximum magnetic field intensity is obtained in the hole and can be used to fully improve MD emitter emission. This indicates that the radiative decay rate (<i>R</i><i>E</i>) of the MD emitter is 965-fold enhanced in the hole and has been achieved with a large quantum efficiency of over 80%. As it can access the magnetic hot spot, it can achieve greater MD emission, which has more advantages than without holes. By forming the dimer, it can be further enhanced with an enhancement factor of the <i>R</i><i>E</i> of the ED emitter of over 130 within the dimer. The achieved enhancement factor significantly exceeds the results obtained in the literature using the metal-dielectric-metal structures. We also investigated the directional properties of the hybridized nanodisks. We show that the hybrid structure exhibits a strong capability for forward far-field scattering and changing the thickness of the Al₂O₃ film that can control the directionality of scattering. Our study offers a viable option for the selective excitation of magnetic and electric emissions in light-matter interactions and opens up new possibilities for enhancing the radiation from the MD emitter.