Continuous 3D Multimodal Buckling Modulated Chiral Responses in Reconfigurable Terahertz Metamaterials

Recent advances of metamaterials (MMs) have opened the door to giant chirality beyond levels of naturally existing media. A variety of tunable chiral MMs are also proposed to realize dynamic chiral effects and the morphologic reconfigurable MMs are widely constructed to modulate chiral responses owing to its simple structural composition. However, the existing reconfigurable MMs can only transform from non-chirality to one chirality under external loadings. Here, a reconfigurable terahertz MM is proposed to realize the multiple modulation of the chiral effect based on the 3D multimodal buckling deformation. The planar MM is initially transformed into a 3D symmetric morphology without chirality by releasing the biaxially pre-stretched substrate. Furtherly, the orthogonal uniaxial loading-path can facilitate two morphologies of MM with opposite chirality. In the above-mentioned continuous deformation process, the circular dichroism can be modulated from -0.18 to 0.18. Our proposed multimodal reconfiguration principle has provided a novel modulation principle of MMs and might extend the reconfigurable meta-devices toward more advanced functional applications.