Enantioselection and chiral sorting of single microspheres using optical pulling forces

TL;DR

This paper introduces a novel all-optical method for enantioselective sorting of chiral microspheres using pulling forces from two circularly polarized light sources, with tunable selectivity based on incident angles.

Contribution

The authors propose a new optical scheme for enantioselection and sorting of chiral microspheres, controllable by incident angles, enabling sorting of particles with very small chiral parameters.

Findings

Enantioselectivity achieved by angle-dependent optical pulling forces.

Method allows sorting of microspheres with arbitrarily small chiral parameters.

External control via incident wavevector angles enables fine-tuning of enantioselectivity.

Abstract

We put forward a novel, twofold scheme that enables at the same time all-optical enantioselection and sorting of single multipolar chiral microspheres based on optical pulling forces exerted by two non-collinear, nonstructured, circularly-polarized light sources. Our chiral resolution method can be externally controlled by varying the angle between their incident wavevectors, allowing for a fine-tuning of the range of chiral indices for enantioselection. Enantioselectivity is achieved by choosing angles such that only particles with the same handedness of the light sources are pulled. This proposal allows one to achieve all-optical sorting of chiral microspheres with arbitrarily small chiral parameters, thus outperforming current optical methods.