Experimental generation of optimally chiral azimuthally-radially polarized beams

TL;DR

This paper reports the experimental creation of a new class of structured light beams, azimuthally-radially polarized beams, that can be tuned to maximize optical chirality, with potential applications in chiral particle sensing and separation.

Contribution

The work introduces and experimentally demonstrates a novel class of optimally chiral structured light beams with precise control over their chirality density.

Findings

Successfully generated paraxial ARPB with controlled features

Demonstrated tunability of chirality density via a single parameter

Showed potential for applications in chiral sensing and enantioseparation

Abstract

We implement a paraxial azimuthally-radially polarized beam (ARPB), a novel class of structured light beams that can be optimal chiral (OC), leading to maximum chirality density at a given energy density. By using vectorial light shaping techniques, we successfully generated a paraxial ARPB with precise control over its features, validating theoretical predictions. Our findings demonstrate the ability to finely adjust the chirality density of the ARPB across its entire range by manipulating a single beam parameter. Although our experimental investigations are primarily focused on the transverse plane, we show that fields whose transverse components satisfy the optimal chirality condition are optimally chiral in all directions, and our results highlight the promising potential of OC structured light for applications in the sensing and manipulation of chiral particles. We show that optical chirality is more general than the concept of handedness. This work represents a significant advancement toward practical optical enantioseparation and enantiomer detection at the nanoscale.