Controllable Chirality Sorting of Particles via Topological Optical Quasiparticles

TL;DR

This paper introduces a novel method for controllable chirality sorting of nanoparticles using focused topological optical quasiparticles, enabling efficient and tunable separation based on particle chirality.

Contribution

It presents a new optical sorting mechanism utilizing focused topological light fields for dynamic, tunable separation of chiral nanoparticles.

Findings

Optical forces exert opposite pushes on particles of opposite chirality.

Sorting distance can be tuned by adjusting topological charges.

The method enables efficient, wide-range chirality sorting.

Abstract

The manipulation and sorting of chiral nanoparticles are of fundamental importance in multidisciplinary fields ranging from biochemistry to nanophotonics. In this study, we propose a novel and controllable chirality sorting mechanism for continuous particle separation using focused topological optical quasiparticles. Specifically, we investigate the sorting dynamics driven by tight-focused optical skyrmions and bimerons consisting of tailored spatial modes. By highly focusing free-space topological structure light fields, we generate intricate non-paraxial focal fields with tailored intensity and topological polarization textures. The sorting dynamics are systematically evaluated under the dipole approximation for fused silica nanoparticles. Our analytical calculation demonstrate that optical forces exert opposite directional pushes on particles of opposite chiralities, enabling highly efficient spatial separation. Notably, we demonstrate that this sorting process is controllable; by tuning the topological charges, the sorting distance can be flexibly tailored and expanded. The dynamic sorting process in customized topological structures introduces a promising new paradigm for tunable, wide-range chirality sorting of micro- and nano-particles.