Chiral and nonlinear resonant metaphotonics

I review the recent trends chiral metaphotonics underpinned by the physics of Mie resonances in high-index dielectric nanoparticles. More specifically, I discuss linear and nonlinear circular dichroism of dielectric resonant metasurfaces. We predict and demonstrate experimentally the enhancement of circular dichroism for normal propagation of light due to the excitation of multipolar Mie-type modes in silicon resonators and the formation of a complex vectorial field structure. High-quality Mie resonances satisfying optimal coupling condition can lead to giant circular dichroism in the nonlinear regime observed for the generation of the third-harmonic signal by normally propagating circularly polarized fundamental frequency fields.