Soft‐MEMS Chiral Reconfigurable Terahertz Metasurfaces Based on Liquid Crystal Elastomer

ABSTRACT The efficient manipulation of the spin angular momentum of electromagnetic waves plays a pivotal role in advancing chirality‐related physics and enabling chirality‐based applications. However, achieving strong and tunable chirality, particularly in the terahertz regime, remains challenging due to constraints in nanofabrication and the difficulty of breaking three‐dimensional (3D) mirror symmetry with sub‐millimeter features. Here, we report a soft‐MEMS‐based reconfigurable chiral metasurface operating in the terahertz regime, using liquid crystal elastomer (LCE) film as a free‐standing substrate. By combining laser cold‐cutting to define independently deformable units and Joule heating from integrated drive circuits to induce out‐of‐plane curling along the wave propagation direction, our design transforms initially planar meta‐atoms into 3D chiral structures, enabling real‐time electrical control of intrinsic chirality. The maximum absolute values of circular dichroism (CD) and optical activity (OA) measured experimentally at the operating frequency were CD = 0.236 and OA = 11.1°, respectively, with modulation depths exceeding 66%. To the best of our knowledge, this is the first LCE‐based chiral optical device, offering a low‐cost, flexible, easy‐to‐fabricate, and cross‐band scalable platform. This work paves the way for fundamental studies of dynamic chirality and holds promise for applications in tunable polarization optics, chiral sensing, and reconfigurable terahertz devices.