All-dielectric metasurfaces comprising arrays of nanostructured high-refractive-index materials are re-imagining what is achievable in terms of the manipulation of light. However, the functionality of conventional dielectric-based metasurfaces is fixed by design; thus, their optical response is locked in at the fabrication stage. A far wider range of applications could be addressed if dynamic and reconfigurable control were possible. We demonstrate this here via the novel concept of hybrid metasurfaces, in which reconfigurability is achieved by embedding sub-wavelength inclusions of chalcogenide phase-change materials within the body of silicon nanoresonators. By strategic placement of an ultra-thin ${{\rm Ge}_2}{{\rm Sb}_2}{{\rm Te}_5}$ layer and reversible switching of its phase-state, we show individual, multilevel, and dynamic control of metasurface resonances. We showcase our concept via the design, fabrication, and characterization of metadevices capable of dynamically filtering and modulating light in the near infrared (O and C telecom bands), with modulation depths as high as 70% and multilevel tunability. Finally, we show numerically how the same approach can be re-scaled to shorter wavelengths via appropriate material selection, paving the way to additional applications, such as high-efficiency vivid structural color generators in the visible spectrum. We believe that the concept of hybrid all-dielectric/phase-change metasurfaces presented in this work could pave the way for a wide range of design possibilities in terms of multilevel, reconfigurable, and high-efficiency light manipulation.

中文翻译：

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混合全介电相变超表面的可重构多级控制

包含纳米结构的高折射率材料阵列的全介电超表面正在重新构想在光的操纵方面可以实现的目标。但是，常规的基于电介质的超表面的功能是通过设计固定的；因此，请参见图5。因此，它们的光学响应在制造阶段就被锁定了。如果可以进行动态和可重新配置的控制，则可以解决更广泛的应用。我们在这里通过混合超颖表面的新颖概念证明了这一点，其中可重构性是通过在硅纳米谐振器体内嵌入硫族化物相变材料的亚波长夹杂物实现的。通过战略性放置超薄$ {{\ rm Ge} _2} {{\ rm Sb} _2} {{\ rm Te} _5} $层和其相态的可逆切换，我们展示了元表面共振的单独，多级和动态控制。我们通过设计，制造和表征能够动态过滤和调制近红外光（O和C电信频段）中的光的元设备来展示我们的概念，调制深度高达70％，并且具有多级可调性。最后，我们通过数值显示了如何通过适当的材料选择将相同的方法重新缩放到较短的波长，从而为其他应用铺平了道路，例如在可见光谱中高效的生动结构颜色生成器。我们相信，这项工作中提出的混合全介电/相变超表面概念可以为多层，可重构，