Shaping the Radiation Pattern of Second-Harmonic Generation from AlGaAs Dielectric Nanoantennas

We study the manipulation of the radiation pattern of second-harmonic generation from AlGaAs all-dielectric nano antennas exhibiting electric and magnetic resonances. We show the importance of the interference of different higher order multipoles in the nonlinear response of dielectric antennas for shaping of their second -harmonic radiation pattern. In particular, we show how such multipolar interference can be engineered in AlGaAs nanodisks by manipulating the pump beam polarization, incidence angle, and disk geometry. In this way we demonstrate the shaping of the radiation pattern in order to increase the second -harmonic power by a factor of 8 when measured in experiment through a finite numerical aperture microscope objective.