Strong second-harmonic generation in dielectric optical nanoantennas resulting from the hybridization of magnetic dipoles and lattice resonances

Abstract

Magnetic dipole resonances supported by high refractive index dielectric nanoparticles have appeared recently as a new alternative to plasmonic nanostructures to manipulate light–matter interactions. The volume field enhancement within the particles significantly boosts some nonlinear processes, mitigating the need for conventional phase-matching conditions. In this paper, we show that by using an AlGaAs nanocylinder array whose lattice resonance spectrally matches the magnetic resonance of individual particles, the two resonances will couple with each other, leading to their strong hybridization and helping achieve a stronger circulation of the electric fields within the particles. As a result of this mode hybridization, at a low pump laser power intensity of 0. 053 G W / c m 2 , the efficiency of second-harmonic generation can be further enhanced by more than 2 orders of magnitude compared to that from an individual nanocylinder.