Tang Fu, Zhong Qinyang, Zhang Xiaoqiuyan, Zhuang Yuxuan, Zhang Tianyu, Xu Xingxing, Hu Min
Terahertz Research Center, School of Electronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China.
Key Laboratory of Terahertz Technology, Ministry of Education, Chengdu 610054, China.
Nanomaterials (Basel). 2024 Nov 30;14(23):1932. doi: 10.3390/nano14231932.
The tunability of spectral lineshapes, ranging from Lorentzian to Fano profiles, is essential for advancing nanoscale photonic technologies. Conventional far-field techniques are insufficient for studying nanoscale phenomena, particularly within the terahertz (THz) range. In this work, we use a U-shaped resonant ring on a waveguide substrate to achieve precise modulation of Lorentzian, Fano, and antiresonance profiles. THz scattering scanning near-field optical microscopy (s-SNOM) reveals the underlying physical mechanism of these transitions, driven by time-domain phase shifts between the background excitation from the waveguide and the resonance of the U-shaped ring. Our approach reveals a pronounced asymmetry in the near-field response, which remains undetectable in far-field systems. The ability to control spectral lineshapes at the nanoscale presents promising applications in characterizing composite nanoresonators and developing nanoscale phase sensors.
光谱线形从洛伦兹分布到法诺分布的可调谐性对于推进纳米级光子技术至关重要。传统的远场技术不足以研究纳米级现象，特别是在太赫兹（THz）范围内。在这项工作中，我们在波导衬底上使用U形谐振环来实现对洛伦兹分布、法诺分布和反谐振分布的精确调制。太赫兹散射扫描近场光学显微镜（s-SNOM）揭示了这些跃迁的潜在物理机制，该机制由来自波导的背景激发与U形环的共振之间的时域相移驱动。我们的方法揭示了近场响应中明显的不对称性，这在远场系统中仍然无法检测到。在纳米尺度上控制光谱线形的能力在表征复合纳米谐振器和开发纳米级相位传感器方面具有广阔的应用前景。
