VO2-介电超表面中非对称重构所实现的新功能

中文摘要 AI 辅助

双各向异性超表面提供了仅通过电和磁响应无法实现的电磁功能，能够实现非对称散射、定向吸收和先进的波前控制。然而，在光学频率下，大多数演示依赖于静态纳米结构，其磁电响应在制造后是固定的。在此，我们研究了利用工作在近红外波段的热可调硅-VO$_2$超表面对电磁双各向异性进行动态重构所带来的机遇。通过将集体极化率框架与数值模拟和实验表征相结合，我们表明VO$_2$的绝缘体-金属转变不仅改变了超表面的电响应和磁响应，还改变了其磁电耦合，从而在单一平台内提供了访问不同双各向异性状态的可能性。温度相关的实验表征证实了吸收非对称性的热驱动演化。基于该框架，我们确定了不同的工作状态，并展示了双各向异性重构如何实现透射和反射定向功能，包括透射功率限制、功率依赖的非对称反射以及功率依赖的吸收率/发射率。这些结果确立了磁电耦合的动态控制作为多功能和自适应光子超表面在光学和热应用中的一个强大自由度。

英文摘要

Bianisotropic metasurfaces provide electromagnetic functionalities that cannot be achieved through electric and magnetic responses alone, enabling asymmetric scattering, directional absorption, and advanced wavefront control. At optical frequencies, however, most demonstrations rely on static nanostructures whose magnetoelectric response is fixed after fabrication. Here, we investigate the opportunities enabled by dynamic reconfiguration of electromagnetic bianisotropy using a thermally tunable silicon--VO$_2$ metasurface operating in the near-infrared. By combining a collective-polarizability framework with numerical simulations and experimental characterization, we show that the insulator-to-metal transition of VO$_2$ modifies not only the electric and magnetic responses of the metasurface, but also its magnetoelectric coupling, providing access to distinct bianisotropic states within a single platform. Temperature-dependent experimental characterization confirms the thermally driven evolution of the absorption asymmetry. Based on this framework, we identify different operational regimes and demonstrate how bianisotropy reconfiguration enables transmissive and reflective directional functionalities, including transmission power-limiting, power-dependent asymmetric reflection, and power-dependent absorptivity/emissivity. These results establish dynamic control of magnetoelectric coupling as a powerful degree of freedom for multifunctional and adaptive photonic metasurfaces for optical and thermal applications.

发表机构

• Nanophotonics Technology Center, Universitat Politècnica de València（瓦伦西亚理工大学纳米光子技术中心）
• Department of Materials Engineering, KU Leuven（荷语鲁汶大学材料工程系）

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