Broadband forward scattering from dielectric cubic nanoantenna in lossless media

Dielectric photonics platform provides unique possibilities to control light scattering via utilizing high-index dielectric nanoantennas with peculiar optical signatures. Despite the intensively growing field of all-dielectric nanophotonics, it is still unclear how surrounding media affect scattering properties of a nanoantenna with complex multipole response. Here, we report on light scattering by a silicon cubic nanoparticle embedded in lossless media, supporting optical resonant response. We show that significant changes in the scattering process are governed by the electro-magnetic multipole resonances, which experience spectral red-shift and broadening over the whole visible and near-infrared spectra as the indices of media increase. Most interestingly, the considered nanoantenna exhibits the broadband forward scattering in the visible and near-infrared spectral ranges due to the Kerker-effect in high-index media. The revealed effect of broadband forward scattering is essential for highly demanding applications in which the influence of the media is crucial such as health-care, e.g., sensing, treatment efficiency monitoring, and diagnostics. In addition, the insights from this study are expected to pave the way toward engineering the nanophotonic systems including but not limited to Huygens-metasurfaces in media within a single framework

Evolution of multipole moments in silicon nanocylinder while varying the refractive index of surrounding medium

Here we use multipole decomposition approach to study optical properties of a silicon nanocylinder in different lossless media. We show that resonant peaks of multipole moments experience red shift, smoothing and broadening. Worth noting that electric multipoles experience bigger red shift than their magnetic counterparts. Our results can be applied to design optical devices within a single framework. © 2020 IOP Publishing Ltd