Magnetic Purcell Enhancement in a Nanoantenna‐Spherical Bragg Resonator Coupled System

Abstract

AbstractIn this work, a novel approach for enhancing magnetic fields in all‐dielectric nanoantennas using Spherical Bragg Resonators (SBR) is proposed, which can boost quantum emitters' magnetic transitions. A matrix method has been used to optimize the magnetic dipole resonance of a SiO2/Si core‐shell spherical nanoantenna. The radiative and non‐radiative decay rate of a Eu3+ emitter with a quantum efficiency of ∼80% is studied. The findings revealed that the magnetic dipole nanoantenna resonance coupling with the SBR mode significantly enhances the modal magnetic field. A 4‐layer SiO2/Si SBR results in a Purcell factor of , the highest it has found in the literature, to the best of the knowledge. The work offers a theoretical demonstration of the potential of SBR to improve the performance of dielectric nanoantennas.