Single photon sources based on semiconductor quantum dots are one of the most prospective elements for optical quantum computing and cryptography. Such systems are often based on Bragg resonators, which provide several ways to control the emission of quantum dots. However, the fabrication of periodic structures with many thin layers is difficult. On the other hand, the coupling of single-photon sources with resonant nanoclusters made of high-index dielectric materials is known as a promising way for emission control. Our experiments and calculations show that the excitation of magnetic Mie-type resonance by linearly polarized light in a GaAs nanopillar oligomer with embedded InAs quantum dots leads to quantum emitters absorption efficiency enhancement. Moreover, the nanoresonator at the wavelength of magnetic dipole resonance also acts as a nanoantenna for a generated signal, allowing control over its radiation spatial profile. We experimentally demonstrated an order of magnitude emission enhancement and numerically reached forty times gain in comparison with unstructured film. These findings highlight the potential of quantum dots coupling with Mie-resonant oligomers collective modes for nanoscale single-photon sources development.

We demonstrated two orders of magnitude enhancement of the third-harmonic intensity for isolated nanoclusters of silicon nanoparticles illuminated by normally incident azimuthally polarized cylindrical vector beams at the wavelength of oligomer’s out-of-plane magnetic mode.

In this work, we demonstrate experimentally and numerically an anisotropic nonlinear optical response from silicon nanoparticle oligomers. By monitoring the third-harmonic generation from symmetric silicon nanodisk trimers as a function of the linear pump polarization orientation, we observe considerable variations in the nonlinear signal stemming from the polarization sensitivity of the local field profiles, which otherwise play no role in the symmetry of the nanostructure linear response.