# Newtonian orbits of nanoparticles interacting with structured light beams

## TL;DR

This paper numerically investigates the dynamics of nanoparticles in structured light beams, revealing conditions for particle expulsion and the formation of spiral orbits influenced by scattering forces and beam structure.

## Contribution

It introduces a comprehensive numerical model considering multiple optical forces to analyze nanoparticle orbits in complex light fields, including vortex and Full-Poincaré beams.

## Key findings

- Particles are expelled from beams regardless of gradient force strength under certain scattering force symmetries.
- Spiral orbits can form under specific conditions and beam types.
- The study highlights the role of scattering forces in nanoparticle dynamics within structured light.

## Abstract

We perform numerical analysis to study the orbits described by subwavelength size particles interacting with structured light beams. Our solution to the particle dynamics considers: (i) the gradient force, (ii) the radiation pressure, and (iii) the force from the curl of the spin angular momentum. The last two terms, (ii) and (iii), constitute the scattering forces. The optical structures of interest are vortices, vector, and Full-Poincar\'{e} beams. From our numerical results, we show that the particle is expelled from the beam, independent of the gradient force intensity if some of the scattering forces have cylindrical symmetry. Furthermore, we found spiral orbits for some particular conditions and types of Full-Poincare beams.