# Asymmetry and spin-orbit coupling of light scattered from subwavelength particles

## TL;DR

This paper investigates how the asymmetry parameter g influences the angular dependence of light scattering, spin-orbit coupling, and polarization effects in subwavelength particles, revealing new links between these phenomena.

## Contribution

It demonstrates that the angular behavior of optical mirages and angular momentum exchange is fully determined by the asymmetry parameter g, independent of specific particle properties.

## Key findings

- Optical mirages and angular momentum exchange maxima occur at different angles for g ≠ 0.
- The asymmetry parameter g is exactly half of the degree of circular polarization at right-angle scattering.
- Single polarization measurements can infer the entire angular scattering properties.

## Abstract

Light scattering and spin-orbit angular momentum coupling phenomena from subwavelength objects, with electric and magnetic dipolar responses, are receiving an increasing interest. Under illumination by circularly polarized light, spin-orbit coupling effects have been shown to lead to significant shifts between the measured and actual position of particles. Here we show that the remarkable angular dependence of these "optical mirages" and those of the intensity, degree of circular polarization (DoCP), and spin and orbital angular momentum of scattered photons, are all linked and fully determined by the dimensionless "asymmetry parameter" g, being independent of the specific optical properties of the scatterer. Interestingly, for g different from 0, the maxima of the optical mirage and angular momentum exchange take place at different scattering angles. In addition we show that the g parameter is exactly half of the DoCP at a right-angle scattering. This finding opens the possibility to infer the whole angular properties of the scattered fields by a single far-field polarization measurement.