Sorting of enantiomers using optical chirality in uniform light field

Abstract

Enantiomer sorting greatly promotes the advancement of chemistry, bioscience, and medicine while also facing significant challenges. Recently, all-optical solutions have attracted considerable interest due to their non-invasiveness. While, it should be noted that the achiral optical force is always much larger than the chiral gradient force that plays a key role in all-optical enantiomer sorting, hindering the separation of enantiomers. Previously proposed methods to boost the chiral gradient forces by plasmonic and photonic nanostructures are often accompanied by the enhancement of achiral optical forces. The sorted chiral particles are also difficult to be transferred from the complex nanostructures. Here, we propose an approach for separating enantiomers using uniform light field formed by two waves, which is capable of sorting deep sub-wavelength chiral particles. In our method, the chiral particles can be sorted within a simple planar structure while the achiral gradient force is equal to zero. Our research reveals a promising perspective on large-scale sorting for enantiomers.