Open Access

The interaction of light and chiral matter is subject of recent research both in fundamental science and applications. Among these are the helicity of electromagnetic fields described with the optical chirality density and emitters sensitive to circular polarization employed in quantum communications. In the weak coupling regime of chiral emitters, we analyze the conversion of chirality which can be regarded as an analogue to absorption of energy describing the change of circular polarization of the incident field. This enables the tailoring of chiral near-fields close to metamaterials, e.g. composed of gold helices, and gives insights into extinction measurements such as circular dichroism. We show relation of the weak and strong coupling regime. The latter can be modelled with cross electric-magnetic polarizabilities or with effective chiral materials, i.e. bi-anisotropic media. Accordingly, we motivate the necessity for rigorous numerical simulations to accurately describe chiral light-matter interaction.