  Dielectric Mie nanoresonators showing strong light-matter interaction at the
nanoscale may enable new functionality in photonic devices. Recently, strong
magneto-optical effects have been observed in magneto-optical nanophotonic
devices due to the electromagnetic field localization. However, most reports so
far have been focused on the enhancement of conventional magneto-optical
effects. Here, we report the observation of circular displacement current
induced anomalous magneto-optical effects in high-index-contrast
Si/Ce:YIG/YIG/SiO2 Mie resonators. In particular, giant modulation of light
intensity in transverse magnetic configuration up to 6.4 % under s-polarized
incidence appears, which is non-existent in planar magneto-optical thin films.
Apart from that, we observe a large rotation of transmitted light polarization
in the longitudinal magnetic configuration under near normal incidence
conditions, which is two orders of magnitude higher than for a planar
magneto-optical thin film. These phenomena are essentially originated from the
unique circular displacement current when exciting the magnetic resonance modes
in the Mie resonators, which changes the incident electric field direction
locally. Our work indicates an uncharted territory of light polarization
control based on the complex modal profiles in all-dielectric magneto-optical
Mie resonators and metasurfaces, which opens the door for versatile control of
light propagation by magnetization for a variety of applications in vectoral
magnetic field and biosensing, free space non-reciprocal photonic devices,
magneto-optical imaging and optomagnetic memories.
