Optical analog of valley Hall effect of 2D excitons in hyperbolic metamaterial
Optical analog of valley Hall effect of 2D excitons in hyperbolic metamaterial
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DOI：
10.1364/optica.404063
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发表时间：
2020-08
期刊：
影响因子：
10.4
通讯作者：
S. Guddala;M. Khatoniar;Nicholas S. Yama;W. Liu;G. Agarwal;V. Menon
中科院分区：
文献类型：
--
作者：
S. Guddala;M. Khatoniar;Nicholas S. Yama;W. Liu;G. Agarwal;V. Menon
二维半导体中电子的自旋和动量谷锁定使得谷自由度对于功能光电器件具有很大的实用性。由于不同谷的光学选择规则的差异，这些谷电子可以被光学寻址。这些材料中的电子和激子表现出谷霍尔效应，其中来自特定谷的载流子在电或热偏压下被引导到不同的方向。在这里，我们报告的光学谷霍尔效应，其中从单层WS2中的谷偏振激子的光发射在不同的方向上传播，由于激子发射的优先耦合到高动量态的双曲型超材料。实验观察到的效果与理论模型的激子发射在近场的双曲介质中证实。使用大块人工光子介质而不需要纳米结构的光谷霍尔效应的演示打开了实现在室温下操作的基于谷的激子电路的可能性。
The robust spin and momentum valley locking of electrons in two-dimensional semiconductors make the valley degree of freedom of great utility for functional optoelectronic devices. Owing to the difference in optical selection rules for the different valleys, these valley electrons can be addressed optically. The electrons and excitons in these materials exhibit valley Hall effect, where the carriers from specific valleys are directed to different directions under electrical or thermal bias. Here we report the optical valley Hall effect where the light emission from the valley polarized excitons in monolayer WS2 propagates in different directions owing to the preferential coupling of excitonic emission to the high momentum states of the hyperbolic metamaterial. The experimentally observed effects are corroborated with theoretical modeling of excitonic emission in the near field of hyperbolic media. The demonstration of the optical valley Hall effect using a bulk artificial photonic media without the need for nanostructuring opens the possibility of realizing valley-based excitonic circuits operating at room temperature.