Zhou Chaobiao, Zhou Mimi, Fu Zhenchu, He Haoxuan, Deng Zi-Lan, Xiang Hong, Chen Xiaoshuang, Lu Wei, Li Guanhai, Han Dezhuan
School of Physics and Mechatronic Engineering, Guizhou Minzu University, Guiyang 550025, China.
College of Physics, Chongqing University, Chongqing 401331, China.
Nano Lett. 2025 Apr 9;25(14):5916-5924. doi: 10.1021/acs.nanolett.5c00967. Epub 2025 Mar 25.
Achieving ultrahigh quality factor optical resonances is crucial for advancing low-threshold lasers, high-sensitivity sensors, and nonlinear photonics. While dielectric metasurfaces supporting quasi-bound states in the continuum (qBICs) show great potential, their experimental realization has been challenging due to the difficulty of precisely controlling symmetry-breaking at the nanoscale. Here, we introduce a precision-controlled symmetry-protected qBIC method using angular perturbations to precisely tune asymmetry, ensuring both high precision and reproducibility of Q-factors. In contrast to traditional SP-qBIC excitation, which relies on uncontrolled asymmetry, our method offers more accurate and consistent control by precisely tuning angular perturbations instead of structural variations. Additionally, our approach defines the lower limit of achievable Q-factors, providing a reliable lower bound. The experimental demonstration of SP-qBICs in composite nanoslit metasurfaces achieves a record-breaking Q-factor of 1.1 × 10-the highest reported for SP-qBICs to date. These findings offer a promising platform for designing ultrahigh-Q resonators for next-generation photonic-applications.
实现超高品质因数的光学共振对于推进低阈值激光器、高灵敏度传感器和非线性光子学至关重要。虽然支持连续体中的准束缚态（qBICs）的介电超表面显示出巨大潜力，但由于在纳米尺度上精确控制对称性破缺的困难，其实验实现一直具有挑战性。在这里，我们介绍一种使用角扰动的精确控制对称保护qBIC方法，以精确调整不对称性，确保品质因数的高精度和可重复性。与依赖于不受控制的不对称性的传统SP-qBIC激发相比，我们的方法通过精确调整角扰动而不是结构变化来提供更准确和一致的控制。此外，我们的方法定义了可实现的品质因数的下限，提供了一个可靠的下限。复合纳米狭缝超表面中SP-qBICs的实验演示实现了创纪录的1.1×10的品质因数——这是迄今为止SP-qBICs报道的最高值。这些发现为设计用于下一代光子应用的超高Q谐振器提供了一个有前景的平台。
