Metasurfaces are usually planar structures and do not possess intrinsic chirality and therefore hardly generate optical activity. Here we realized a tunable optical activity in a terahertz wave through a microfluid-based soft metasurface. The meta-atom is a chiral structured microchannel made of soft polydimethylsiloxane and injected with the liquid metal Galinstan. A microfluid pressure system is bonded to the metasurface to reconfigure all meta-atoms simultaneously. By pumping glycerol liquid into the pressure system, the metasurface is deformed from a planar structure to a three dimensional one, which manifests intrinsic chirality for optical activity realization. By controlling the injected glycerol volume, a polarization rotation from 0°to 14° at 0.19 THz is demonstrated. The soft metasurface with tunable optical activity can be flexibly applied in various applications such as polarization microscopy, bio-detection and material analysis, etc.

中文翻译：

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基于微流体的软亚表面可在太赫兹波中调节光学活动

超表面通常是平面结构，不具有固有手性，因此几乎不产生光学活性。在这里，我们通过基于微流体的软超表面在太赫兹波中实现了可调节的光学活动。所述间位原子是由柔软的聚二甲基硅氧烷制成的手性结构化微通道，并注入了液态金属Galinstan。将微流体压力系统结合到超颖表面，以同时重新配置所有超颖原子。通过将甘油液体泵入压力系统中，超颖表面从平面结构变形为三维结构，这体现了实现光学活性的内在手性。通过控制注入的甘油体积，可以证明在0.19 THz下从0°到14°的偏振旋转。