Phase Enabled Circular Dichroism Reversal in Twisted Bi-Chiral Propeller Metamolecule Arrays

Artificial chiral structures play a crucial role in the realization of strong chiroptical responses and flexible light manipulation. Here, a unique bi-chiral propeller metamolecule array is demonstrated in which the geometric chirality of the subunit with intracellular blades is opposite to that of the subunit with intercellular blades. Benefited from the special propeller twists, it is demonstrated that the propeller metamolecule arrays support the phase controlled chiral surface lattice resonances, whose amplitude can be tailored by tuning the coupling of chiral centers to change the interference phase. Specifically, the circular dichroism of the metamolecule array is readily reversed by rotating the propeller blades without changing the local geometry and the lattice parameters. The proposed bi-chiral propeller metamolecule array and the exotic circular dichroism reversal are further demonstrated in experiments by adopting a nano-kirigami fabrication method. This work provides a novel paradigm to investigate the profound chiroptical responses and manipulate the advanced spin states of light.