Tunable unidirectional surface plasmon polaritons at the interface between gyrotropic and isotropic conductors
Tunable unidirectional surface plasmon polaritons at the interface between gyrotropic and isotropic conductors
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DOI：
10.1364/optica.425290
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发表时间：
2021-07-20
期刊：
影响因子：
10.4
通讯作者：
Cen, Cheng
中科院分区：
文献类型：
--
作者：
Liang, Yi;Pakniyat, Samaneh;Cen, Cheng
单向传播的电磁波在自然界中很少见，但由于其在无后向散射光学信息处理装置中的潜在应用而备受追捧。理论上表明，回转金属和各向同性金属具有不同的体光学能带拓扑结构，可以在它们的界面产生具有拓扑保护的单向表面等离子体激元(SPPs)。在这里，我们在实验上识别了太赫兹频率下的这种界面模。通过定制的光栅耦合器发射界面SPP，得到的远场光谱数据揭示了强烈的非互易SPP色散，与理论预测高度一致。本文所研究的界面表面等离子体激活剂的方向性可以通过改变外场或调整块体材料的金属特性来灵活地调节。主动可调谐单向表面等离子体激元的实验实现，为开发基于拓扑保护界面波的纳米光子信息处理器件奠定了基础。(C)OSA开放获取出版协议条款下的2021年美国光学学会
Unidirectionally propagated electromagnetic waves are rare in nature but heavily sought after due to their potential applications in backscatter-free optical information processing setups. It was theoretically shown that the distinct bulk optical band topologies of a gyrotropic metal and an isotropic metal can enable topologically protected unidirectional surface plasmon polaritons (SPPs) at their interface. Here, we experimentally identify such interfacial modes at terahertz frequencies. Launching the interfacial SPPs via a tailored grating coupler, the far-field spectroscopy data obtained reveals strongly nonreciprocal SPP dispersions that are highly consistent with the theoretical predictions. The directionality of the interfacial SPPs studied here is flexibly tunable by either varying the external field or adjusting the metallic characteristics of the bulk materials. The experimental realization of actively tunable unidirectional SPPs sets the foundation for developing nanophotonic information processing devices based on topologically protected interfacial waves. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement