Optical chirality without optical activity: How surface plasmons give a twist to light

TL;DR

This paper demonstrates that surface plasmons on twisted planar nanostructures can produce optical effects akin to optical activity, revealing a new form of optical chirality without traditional optical activity in the visible spectrum.

Contribution

It introduces a novel experimental observation of optical chirality manifesting through surface plasmons on planar nanostructures, expanding understanding of light-matter interactions.

Findings

Surface plasmons enable optical chirality in planar nanostructures.

Chirality manifests differently in these structures compared to traditional optical activity.

Experimental polarization tomography confirms the effect in the visible domain.

Abstract

Light interacts differently with left and right handed three dimensional chiral objects, like helices, and this leads to the phenomenon known as optical activity. Here, by applying a polarization tomography, we show experimentally, for the first time in the visible domain, that chirality has a different optical manifestation for twisted planar nanostructured metallic objects acting as isolated chiral metaobjects. Our analysis demonstrate how surface plasmons, which are lossy bidimensional electromagnetic waves propagating on top of the structure, can delocalize light information in the just precise way for giving rise to this subtle effect.