Optical force and torque on small particles induced by polarization singularities

TL;DR

This paper investigates how optical polarization singularities generated by a gold cylinder influence the force and torque on small particles, revealing complex spatial behaviors and potential applications in optical manipulation and sensing.

Contribution

It uncovers, for the first time, the effect of polarization singularities on light-induced forces and torques on small particles, advancing understanding of chiral light-matter interactions.

Findings

Polarization singularities induce complex force and torque patterns.

Scattering from a gold cylinder creates electric and magnetic C lines.

Spatial variations of forces and torques exhibit interesting symmetry properties.

Abstract

Optical forces in the near fields have important applications in on-chip optical manipulations of small particles and molecules. Here, we report a study of optical force and torque on small particles induced by the optical polarization singularities of a gold cylinder. We show that the scattering of the cylinder generates both electric and magnetic C lines (i.e., lines of polarization singularities) in the near fields, and the C lines can induce complex force and torque on a dielectric/magnetic particle. The force and torque manifest dramatic spatial variations with interesting symmetry properties, providing rich degrees of freedom for near-field optical manipulations. The study, for the first time to our knowledge, uncovers the effect of optical polarization singularities on light-induced force and torque on small particles. The results contribute to the understanding of chiral light-matter interactions and can find applications in on-chip optical manipulations and optical sensing.