Sang Yungang, Wang Chun-Yuan, Raja Soniya S, Cheng Chang-Wei, Huang Chiao-Tzu, Chen Chun-An, Zhang Xin-Quan, Ahn Hyeyoung, Shih Chih-Kang, Lee Yi-Hsien, Shi Jinwei, Gwo Shangjr
Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan.
Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China.
Nano Lett. 2021 Mar 24;21(6):2596-2602. doi: 10.1021/acs.nanolett.1c00198. Epub 2021 Mar 9.
Non-Hermitian photonic systems with gains and/or losses have recently emerged as a powerful approach for topology-protected optical transport and novel device applications. To date, most of these systems employ coupled optical systems of diffraction-limited dielectric waveguides or microcavities, which exchange energy spatially or temporally. Here, we introduce a diffraction-unlimited approach using a plasmon-exciton coupling (polariton) system with tunable plasmonic resonance (energy and line width) and coupling strength. By designing a chirped silver nanogroove cavity array and coupling a single tungsten disulfide monolayer with a large contrast in resonance line width, we show the tuning capability through energy level anticrossing and plasmon-exciton hybridization (line width crossover), as well as spontaneous symmetry breaking across the exceptional point at zero detuning. This two-dimensional hybrid material system can be applied as a scalable and integratable platform for non-Hermitian photonics, featuring seamless integration of two-dimensional materials, broadband tuning, and operation at room temperature.
具有增益和/或损耗的非厄米光子系统最近已成为实现拓扑保护光传输和新型器件应用的一种强大方法。迄今为止，这些系统大多采用衍射极限介质波导或微腔的耦合光学系统，它们在空间或时间上交换能量。在此，我们介绍一种使用具有可调谐等离子体共振（能量和线宽）及耦合强度的等离子体 - 激子耦合（极化激元）系统的无衍射方法。通过设计一个啁啾银纳米凹槽腔阵列，并将具有大共振线宽对比度的单个二硫化钨单层进行耦合，我们展示了通过能级反交叉和等离子体 - 激子杂化（线宽交叉）进行调谐的能力，以及在零失谐时跨越例外点的自发对称性破缺。这种二维混合材料系统可作为非厄米光子学的可扩展且可集成平台，具有二维材料的无缝集成、宽带调谐以及室温下运行的特点。
