Department of Mechanical Engineering, Vanderbilt University, Nashville, TN, 37212, USA.
Department of Physics and Astronomy, University of Georgia, Athens, GA, 30602-2451, USA.
Nat Commun. 2018 Oct 22;9(1):4371. doi: 10.1038/s41467-018-06858-y.
Metasurfaces control light propagation at the nanoscale for applications in both free-space and surface-confined geometries. However, dynamically changing the properties of metasurfaces can be a major challenge. Here we demonstrate a reconfigurable hyperbolic metasurface comprised of a heterostructure of isotopically enriched hexagonal boron nitride (hBN) in direct contact with the phase-change material (PCM) single-crystal vanadium dioxide (VO). Metallic and dielectric domains in VO provide spatially localized changes in the local dielectric environment, enabling launching, reflection, and transmission of hyperbolic phonon polaritons (HPhPs) at the PCM domain boundaries, and tuning the wavelength of HPhPs propagating in hBN over these domains by a factor of 1.6. We show that this system supports in-plane HPhP refraction, thus providing a prototype for a class of planar refractive optics. This approach offers reconfigurable control of in-plane HPhP propagation and exemplifies a generalizable framework based on combining hyperbolic media and PCMs to design optical functionality.
超表面在纳米尺度上控制光的传播，可应用于自由空间和表面受限的几何形状。然而，动态改变超表面的特性可能是一个主要挑战。在这里，我们展示了一种由同位素富集的六方氮化硼（hBN）与相变材料（PCM）单晶氧化钒（VO）直接接触组成的可重构双曲超表面。VO 中的金属和介电畴提供了局部介电环境的空间局部变化，从而能够在 PCM 畴界处发射、反射和传输双曲声子极化激元（HPhP），并通过 1.6 倍的因子调节在 hBN 中传播的 HPhP 的波长。我们表明，该系统支持平面内 HPhP 折射，从而为一类平面折射光学器件提供了原型。这种方法提供了对平面内 HPhP 传播的可重构控制，并体现了一种基于结合双曲介质和 PCM 来设计光学功能的可推广框架。
