Tunable chiral responses in mechanically reconfigurable three-dimensional metamaterials

Abstract

The active manipulation of polarization state is of fundamental importance to functional devices integrated in modern terahertz (THz) systems. The emerging chiral metamaterials (MMs) provide enormous possibilities to control the polarization state of incident THz wave, however, existing MMs with strong chirality are normally insufficient to modulate the circular dichroism (CD). Here, we have proposed a conceptual 3D mechanically reconfigurable chiral MM that is capable of tailoring the right circular polarization transmission and linear-to-circular polarization conversion. The 3D MM morphology can be reproducibly controlled by alternating the pre-strain on the elastic substrate, which allows to provide a flexible route to reconfigure the structural chirality and modulate the chiral response. Additionally, CD spectra exhibit high sensitivity to the rotation angle of MM component. The mechanically tunable chiral MM with high flexibility will build up an efficient approach for the CD enhancement and modulation and paves a novel avenue toward the reconfigurable design principle of flexible functional THz devices.