Meta- Optics with Mie Resonances
In nanophotonics, subwavelength localization of light is usually associated with plasmonics, the collective excitation of electrons and electromagnetic waves at metallic surfaces. Recent developments in the physics of high-index dielectric nanoparticles, however, suggest an alternative mechanism of light localization: low-order dipole and higherorder multipole Mie resonances. These resonances can generate a strong magnetic response that can be leveraged in designing metasurfaces with unidirectional scattering, as well as efficient metadevices. Indeed, as the power of this approach becomes increasingly apparent, high-index nanomaterials could complement, or even substitute for, plasmonic materials in a range of devices—and could spur a new era in nonlinear nanophotonics.