Wave plates as important polarization control devices are widely used in the applications of biomedical imaging, fiber optical communication, astronomy, semiconductor industry and aerospace etc. To make the wave plate actively tunable, we propose a rectangular antenna-based metasurface based on the phase-changing material Ge2Sb2Te5 (GST) with high transmittance and polarization conversion rate. Before the GST phase transition, the metasurface operates as a quarter-wave plate in the wavelength range of 10.0–11.9 μm. After the GST turning into crystalline state, the metasurface operates as a half-wave plate in the wavelength range of 10.3–10.9 μm. The physical mechanism for the high transmittance efficiency and polarization conversion rate attributes to the combination of the electric dipole and magnetic dipole resonances. Moreover, the adjustable wavelength range can be further extended by changing the geometry of antenna-based GST to selectively enhancing or suppressing the electric and magnetic resonances. This work provides a new strategy for tunable wave plate, which would have the potential in the application of multi-functional integrated optical systems.

中文翻译：

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基于相变超表面的可切换四分之一波片和半波片

波片作为重要的偏振控制器件被广泛应用于生物医学成像、光纤通信、天文学、半导体工业和航空航天等领域。为了使波片主动可调，我们提出了一种基于相位的矩形天线超表面。改变材料 Ge2Sb2Te5 (GST) 具有高透射率和偏振转换率。在 GST 相变之前，超表面在 10.0-11.9 μm 的波长范围内用作四分之一波片。在 GST 转变为结晶态后，超表面在 10.3-10.9 μm 的波长范围内作为半波片工作。高透射效率和极化转换率的物理机制归因于电偶极子和磁偶极子共振的组合。而且，通过改变基于天线的 GST 的几何形状来选择性地增强或抑制电和磁共振，可以进一步扩展可调波长范围。这项工作为可调谐波片提供了一种新的策略，在多功能集成光学系统的应用中具有潜力。