Chirality control in metamaterials by geometrical manipulation

Chirality index of chiral structures can be controlled by adjusting the structure geometry. Bi-layer C_n structures are modified to break symmetry of the structure pair, aiming to generate cross coupling terms between electric and magnetic fields. As the bi-layer structures are twisted, in both normal and mirror orientations, chirality index can be then generated, while the number of axes and the angle between the main axis and the connected arm also play a significant role. The most interesting case is the non twisted mirror bi-layer where the resonance indices are envisioned. The results have shown several possibilities of effectively controlling chirality index in metamaterial structures, which will be beneficial in wave controlling devices.