Enhanced spin-orbit optical mirages from dual nanospheres

TL;DR

This paper demonstrates that high refractive index dielectric nanoparticles can produce significantly enhanced spin-orbit optical mirages due to the interplay of electric and magnetic responses, especially under dual symmetry conditions.

Contribution

It reveals how the optical mirage effect is amplified in dielectric nanoparticles when electric and magnetic dipolar responses are balanced, linked to optical vortex formation.

Findings

Enhanced optical mirages occur at the first Kerker condition.

Optical vortex emerges in backscattering direction.

Displacement exceeds wavelength under dual symmetry.

Abstract

Spin-orbit interaction of light can lead to the so-called optical mirages, i.e. a perceived displacement in the position of a particle due to the spiraling structure of the scattered light. In electric dipoles, the maximum displacement is subwavelength and does not depend on the optical properties of the scatterer. Here we will show that the optical mirage in high refractive index dielectric nanoparticles depends strongly on the ratio between electric and magnetic dipolar responses. When the dual symmetry is satisfied (at the first Kerker condition), there is a considerable enhancement (far above the wavelength) of the spin-orbit optical mirage which can be related to the emergence of an optical vortex in the backscattering direction.