Dispersionless optical activity in metamaterials

TL;DR

This paper presents a novel chiral metamaterial exhibiting strong, dispersionless optical activity with minimal ellipticity, achieved through a meta-molecule design that couples magnetic and electric responses, optimized by adjusting the twist angle.

Contribution

The work introduces a new metamaterial design combining a meta-atom and its complement to produce non-resonant, low-dispersion optical activity with enhanced control via twist angle adjustments.

Findings

Achieves strong optical activity with low dispersion at transmission resonance.

Demonstrates coupling of magnetic and electric dipole responses in the meta-molecule.

Optimizes optical activity by varying the twist angle.

Abstract

We introduce a chiral metamaterial with strong, non-resonant optical activity, and very low polarization ellipticity. We achieve this by combining a meta-atom and its complementary structure into a meta-molecule, resulting in the coupling of magnetic and electric dipole responses. In contrast to either a pair of crosses, or complementary crosses, this structure has low dispersion in the optical activity at the transmission resonance. We also study the excitation mechanism in this structure, and optimize the optical activity through changing the twist angle.