Liquid crystals self-assemble on nanopatterned alignment layers into purely soft matter metasurfaces sensitive to external stimuli and imparting tailored spatial modulations to transmitted light wavefronts. Upon fine optimization, they are capable of efficient light deflection by virtue of anomalous refraction into a dominating transmission diffraction order. To expand the spectral range and acquire additional functionality, we put forward the double-sided metasurface design based on the liquid crystal alignment by a pair of complementing patterned substrates. We numerically optimize, fabricate, and experimentally characterize metasurfaces refracting red light with an efficiency of up to 70% and sustaining the efficiency above 50% in a broad range of visible wavelengths exceeding 500 nm. We verify that the refraction is reversibly switched in less than 10 ms by voltages of a few volts. We also report on a remarkable mechanical reconfigurability, as micrometer-scale relative substrate shift flips the refraction direction.

中文翻译：

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用于电气和机械控制宽带可见异常折射的双面液晶超表面

液晶在纳米图案排列层上自组装成对外部刺激敏感的纯软物质超表面，并为透射光波前提供定制的空间调制。经过精细优化，它们能够通过异常折射有效地将光偏转成主要的透射衍射级。为了扩大光谱范围并获得额外的功能，我们提出了基于一对互补图案基板的液晶排列的双面超表面设计。我们对超表面进行数值优化、制造和实验表征，以高达 70% 的效率折射红光，并在超过 500 nm 的广泛可见波长范围内保持超过 50% 的效率。我们验证通过几伏电压在不到 10 毫秒内可逆地切换折射。我们还报告了显着的机械可重构性，因为微米级的相对基板偏移翻转了折射方向。