The perspective of topological photonics for on-chip terahertz modulation and sensing
The perspective of topological photonics for on-chip terahertz modulation and sensing
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DOI：
10.1063/5.0170233
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发表时间：
2023-11
期刊：
影响因子：
5.6
通讯作者：
Yiwen Sun;Zhijie Mei;Xuejiao Xu;Qingxuan Xie;Shuting Fan;Zhengfang Qian;Xudong Liu
中科院分区：
文献类型：
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作者：
Yiwen Sun;Zhijie Mei;Xuejiao Xu;Qingxuan Xie;Shuting Fan;Zhengfang Qian;Xudong Liu
太赫兹（THz）技术在过去几十年中取得了重大进展，包括太赫兹量子光学等基础科学研究，以及第六代通信，医学成像和生物传感等高度应用领域。然而，片上太赫兹集成波导的进展仍然落后于太赫兹源和探测器的进展。这归因于诸如微带线、共面和中空波导中的欧姆损耗、庞大的占用空间以及在传统电介质波导中的急弯或缺陷处发生的反射和散射损耗等问题。受凝聚态系统中的量子霍尔效应和拓扑绝缘体的启发，最近对光的拓扑相的发现导致了拓扑波导的发展。这些波导表现出显著的现象，如鲁棒的单向传播和对杂质或缺陷的无反射行为。因此，它们为THz片上应用带来了巨大的希望。虽然THz光子拓扑绝缘体（PTIs），包括波分，多端口耦合器和谐振腔，已被证明覆盖800-2500 nm的波长范围，可调谐THz PTIs的研究仍然有限。从这个角度来看，我们简要回顾了几个可调PTIs的例子，主要集中在红外范围内。此外，我们提出了这些设计如何有利于太赫兹片上PTIs的发展。我们探讨了通过光学、电学和热学手段实现可调谐THz PTIs的潜在方法。此外，我们提出了一种设计的太赫兹PTIs的潜在的片上传感应用。为了支持我们的推测，进行了几次模拟，为未来的太赫兹片上PTI设计提供了有价值的见解。
Terahertz (THz) technology has seen significant advancements in the past decades, encompassing both fundamental scientific research, such as THz quantum optics, and highly applied areas like sixth-generation communications, medical imaging, and biosensing. However, the progress of on-chip THz integrated waveguides still lags behind that of THz sources and detectors. This is attributed to issues such as ohmic losses in microstrip lines, coplanar and hollow waveguides, bulky footprints, and reflection and scattering losses occurring at sharp bends or defects in conventional dielectric waveguides. Inspired by the quantum Hall effects and topological insulators in condensed matter systems, recent discoveries of topological phases of light have led to the development of topological waveguides. These waveguides exhibit remarkable phenomena, such as robust unidirectional propagation and reflectionless behavior against impurities or defects. As a result, they hold tremendous promise for THz on-chip applications. While THz photonic topological insulators (PTIs), including wave division, multiport couplers, and resonant cavities, have been demonstrated to cover a wavelength range of 800–2500 nm, research on tunable THz PTIs remains limited. In this perspective, we briefly reviewed a few examples of tunable PTIs, primarily concentrated in the infrared range. Furthermore, we proposed how these designs could benefit the development of THz on-chip PTIs. We explore the potential methods for achieving tunable THz PTIs through optical, electrical, and thermal means. Additionally, we present a design of THz PTIs for potential on-chip sensing applications. To support our speculation, several simulations were performed, providing valuable insights for future THz on-chip PTI designs.