Perfect magnetic mirror based on magnetic dipole scattering in all-dielectric resonators

Abstract

Perfect magnetic mirrors are important optical devices for the development of novel optical detectors, solar cells, and imaging devices. They have the property of only reversing the magnetic field of a light wave upon reflection, for instance, in functional optical metasurfaces. To design an optical magnetic mirror, high-refractive-index dielectric nanostructures that support strong magnetic dipole (MD) response in the optical wavelength range are used. However, the spectral overlap between the MD and electric dipole in dielectric resonators degrades the magnetic mirror reflection. Here, we propose and demonstrate a perfect optical magnetic mirror metasurface that totally reflects an incident wave without electric field phase change. In this perfect magnetic mirror, the electric dipole radiation is completely suppressed by the radiation of the anapole mode in the spectral range where the destructive interference between the electric dipole and toroidal dipole occurs. By fine-tuning the size parameters of the dielectric resonators, we show near-perfect MD scattering as a result of the spectral overlap between MD resonance and anapole mode. The optical magnetic mirror can be tuned from the visible to near-infrared range by scaling the sizes of the resonators. The MD scattering resonators promote the perfect magnetic mirror, a promising platform for designing photodetectors, biological sensors, and reflected waveplates.