Anomalous unidirectional excitation of high-k hyperbolic modes using all-electric metasources
Anomalous unidirectional excitation of high-k hyperbolic modes using all-electric metasources
复制标题
使用全电元源的高 k 双曲模式的反常单向激励
DOI：
10.1117/1.ap.3.3.036001
复制
发表时间：
2021-05-01
影响因子：
17.3
通讯作者：
Chen, Hong
中科院分区：
文献类型：
--
作者：
Guo, Zhiwei;Long, Yang;Chen, Hong
近场光学模式的单向激发是许多光子应用（如无线电力传输和信息通信）的基本前提。我们通过实验构建了全电惠更斯源和自旋超表面源，并在两种双曲超表面中展示了高波矢双曲模式的反常单向激发。我们使用惠更斯源来研究平面双曲超材料（HMM）中双曲体模式的单向激发。具体而言，在垂直方向上的单向激发与自由空间中的相同，但在水平方向上与自由空间中的相反。这种反常的单向激发是由各向异性的HMM色散决定的。此外，我们使用自旋源来观察平面双曲波导中的反常光子自旋霍尔效应。对于具有特定自旋的近场源，由于自旋 - 动量锁定，具有固定方向波矢的导模被激发。由于HMM波导中动量和能量流的方向相反，双曲导模的单向激发是反向的。我们的研究结果不仅揭示了超表面源在近场中的复杂电磁功能，还可能为集成光学器件的发展提供新的机遇。
Abstract. The unidirectional excitation of near-field optical modes is a fundamental prerequisite for many photonic applications, such as wireless power transfer and information communications. We experimentally construct all-electric Huygens and spin metasources and demonstrate anomalous unidirectional excitation of high-k hyperbolic modes in two types of hyperbolic metasurfaces. We use a Huygens metasource to study the unidirectional excitation of hyperbolic bulk modes in a planar hyperbolic metamaterial (HMM). Specifically, unidirectional excitation is the same as that in free space in the vertical direction, but opposite to that in free space in the horizontal direction. This anomalous unidirectional excitation is determined by the anisotropic HMM dispersion. In addition, we use a spin metasource to observe the anomalous photonic spin Hall effect in a planar hyperbolic waveguide. For a near-field source with a specific spin, the guide mode with a fixed directional wave vector is excited due to spin-momentum locking. Because the directions of momentum and energy flows in the HMM waveguide are opposite, the unidirectional excitation of hyperbolic guided modes is reversed. Our results not only uncover the sophisticated electromagnetic functionalities of metasources in the near-field but may also provide novel opportunities for the development of integrated optical devices.