# Interaction of light carrying orbital angular momentum with a chiral dipolar scatterer

## TL;DR

This paper demonstrates that a dipolar chiral nanostructure can distinguish the orbital angular momentum of light, revealing new insights into chiral light-matter interactions and the role of OAM.

## Contribution

It shows that a point-like chiral nanostructure can sense the vorticity of light carrying orbital angular momentum, a previously debated capability.

## Key findings

- Chiral nanostructure distinguishes the sign of OAM in light.
- Conversion of OAM to optical chirality upon focusing.
- Deeper understanding of chiral light-matter interactions.

## Abstract

The capability to distinguish the handedness of circularly polarized light is a well-known intrinsic property of a chiral nanostructure. It is a long-standing controversial debate, however, whether a chiral object can also sense the vorticity, or the orbital angular momentum (OAM), of a light field. Since OAM is a non-local property, it seems rather counter-intuitive that a point-like chiral object could be able to distinguish the sense of the wave-front of light carrying OAM. Here, we show that a dipolar chiral nanostructure is indeed capable of distinguishing the sign of the phase vortex of the incoming light beam. To this end, we take advantage of the conversion of the sign of OAM, carried by a linearly polarized Laguerre-Gaussian beam, into the sign of optical chirality upon tight focusing. Our study provides for a deeper insight into the discussion of chiral light-matter interactions and the respective role of OAM.