Maximized Circular Dichroism induced by Geometrical Parameters in Twisted Layered Chiral Metamaterials

Abstract

We have studied twisted layered chiral metamaterials (TLCMs) which have three twisted-layers with C4-symmetric unit cell. Chiral metamaterials which exhibit broken mirror symmetry have the potential to be used for many sensing applications. However, most of previously reported chiral metamaterials exhibit weak chiroptical property, thus practical applications of chiral metamaterials are hindered. Here, we propose the TLCMs and corresponding enhanced circular dichroism (CD) which is derived from the layer coupling effect.In this work, the relationship between the chiroptical quantity (CD) and the geometrical parameters (e.g. layer thickness and twisted angle of each layer) are studied. Although the many researchers have studied the chirality due to the twisted angle and the nondispersive bi-layer chiral metamaterials but, the maximized CD depending on the layer position is not conducted. We will provide a generalized way to enhance CD response in TLCMs having C4 symmetric multi-layers.1