# Individual plasmonic helix for probing light chirality

## TL;DR

This paper demonstrates that a single plasmonic nanohelix can locally probe light's chirality with high spatial and spectral resolution, enabling advanced chiroptical sensing and mapping.

## Contribution

It introduces a novel plasmonic nanohelix-based probe that selectively transmits circularly polarized light matching its handedness, with potential for high-resolution chiroptical applications.

## Key findings

- Nanohelix transmits same-handed circular polarization
- Asymmetric response is localized and broadband
- Potential for high-resolution chiroptical sensing

## Abstract

We investigate the plasmonic nanohelix as an individual subwavelength element for locally probing light chirality. We show that an hybrid nanoantenna combining a carbon-gold core-shell helix and a plasmonic nanoaperture transmits circularly polarized light with the same handedness as the helix and blocks the other. Such an assymmetric response is spatially localized, spectrally broadband and background-free. Finally, we demonstrate the possibility to engineer an individual plasmonic helix at the apex of a sharp tip typically used in scanning near-field microscopies, thus opening the prospect of moveable local probes for high resolution sensing and mapping of light chirality and chiroptical forces