Realization of Photonic Topological Insulators at Terahertz Frequencies Characterized by Time-Domain Spectroscopy
Realization of Photonic Topological Insulators at Terahertz Frequencies Characterized by Time-Domain Spectroscopy
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时域光谱表征的太赫兹频率光子拓扑绝缘体的实现
DOI：
10.1103/physrevapplied.18.064025
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发表时间：
2022-12
影响因子：
4.6
通讯作者：
Xiao-Hua Deng
中科院分区：
文献类型：
--
作者：
Yun Shen;Jie Ji;Hui-Chang Li;Le Zhang;Xin Yu;Shu-Bin Yan;Mattias Rasmussen;Qian Shen;Daena Madhi;Bin-Bin Zhou;Peter Uhd Jepsen;Xiao-Hua Deng
拓扑系统对无序和连续扰动具有固有的鲁棒性，导致量子固体中电子的无耗散边缘传输，或以拓扑不变量为特征的经典波系统中光子和声子的无反射引导。在技术上重要的太赫兹（THz）频率范围内实现鲁棒、无损的拓扑绝缘体引起了极大的关注。在本文中，我们提出了一个Kagome晶格结构，支持拓扑边缘状态与谷依赖的运输。随后制备了光学拓扑绝缘体，其中镜像对称性被破坏，并且在能带结构的谷处简并态被提升。理论和数值分析表明，可以得到四种类型的边缘状态。利用太赫兹时域光谱（TDS）对所制备的拓扑波导进行了性能表征。在0.437-0.453-THz范围内，几乎相同的THz波传输被验证与直线拓扑波导和Z形波导与多个尖锐的转折角，这定量地说明了强大的后向散射抑制效果从非平凡的拓扑边缘状态的结构。特别是，太赫兹TDS测量提供了重要的额外的时域信息的拓扑波导模式，这是一般无法从以前的拓扑绝缘体调查仅仅回答功率谱测量。
Topological systems are inherently robust to disorder and continuous perturbations, resulting in dissipation-free edge transport of electrons in quantum solids, or reflectionless guiding of photons and phonons in classical wave systems characterized by topological invariants. Realization of robust, lossless topological insulators in the technologically important terahertz (THz) frequency range has drawn immense attention. In this paper, we propose a Kagome lattice structure that supports topological edge states with valley-dependent transport. Optical topological insulators are subsequently fabricated, in which mirror symmetry is broken and degenerate states are lifted atvalleys in the band structure. Theoretical and numerical analyses show that four types of edge states can be obtained. The performance of the fabricated topological waveguides is characterized with THz time-domain spectroscopy (TDS). Nearly identical THz wave transmission in the 0.437–0.453-THz range is verified with a straight-line topological waveguide and Z-shaped waveguides with multiple sharp turning corners, which quantitatively illustrate the strong backscattering suppression effects from the nontrivial topology edge states of the structures. Particularly, the THz TDS measurements provide important extra time-domain information about the topological waveguiding mode, which is generally unavailable from previous topological insulator investigations solely replying on power spectrum measurements.
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影响因子：
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作者：
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DOI：
10.1073/pnas.1525502113
发表时间：
2016-05-03
影响因子：
11.1
作者：
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通讯作者：
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