Period tunability of gratings is extremely desirable for reconfigurable optics. In this study, we report a period-tunable metagrating featuring a bi-layered structure of silicon subwavelength gratings to form a Moiré pattern. Our design is based on the near field Moiré effect and employs the leaky mode resonance to enhance the far-field diffraction. The period of the metagrating can be continuously tuned to its double with the in-plane rotation of the silicon subwavelength gratings. Our simulations indicate that the metagrating exhibits efficient polarization-sensitive diffraction during period-tuning near 1550 nm. Potentially, this metagrating with a wide range of period tunability can be instrumental in developing versatile active optical applications.

中文翻译：

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双层硅转移在近红外区域的周期可调性

光栅的周期可调谐性对于可重构光学器件是非常需要的。在这项研究中，我们报告了一种周期可调的迁移，其特征是硅亚波长光栅的双层结构形成了莫尔图案。我们的设计基于近场莫尔效应，并采用泄漏模式共振来增强远场衍射。通过硅亚波长光栅的面内旋转，可以将迁移周期连续调至两倍。我们的模拟表明，在1550 nm附近的周期调谐过程中，该迁移显示出有效的偏振敏感衍射。潜在地，这种具有广泛的周期可调性的迁移可能有助于开发通用的有源光学应用。