Experimental evidence of giant pure optical activity in a metasurface based on a complementary twisted cross configuration

TL;DR

This paper demonstrates experimentally that a metasurface with a complementary twisted cross design exhibits giant, pure optical activity with minimal circular dichroism, and explores multilayer configurations for bandwidth enhancement.

Contribution

The study provides the first experimental evidence of giant pure optical activity in a metasurface with a complementary twisted cross design and introduces multilayer systems for bandwidth broadening.

Findings

Giant optical activity observed with negligible circular dichroism.

Dual band behavior achieved through multilayer coupling.

Theoretical analysis of layer separation effects on transmission spectra.

Abstract

This work presents an experimental study of giant and pure optical activity in a periodic structure consisting of twisted crosses and complementary crosses patterned on the sides of a copper coated dielectric board. Additionally, a multilayer system is proposed and numerically studied to broaden the transmission bandwidth. Our results show that a dual band behavior can be obtained due to coupling effects between the layers whilst maintaining the dispersionless giant optical activity and negligible circular dichroism. We theoretically study the effect of the separation between layers and its influence on the transmission spectra.