正交平带启用的通过布里渊区折叠实现的鲁棒法诺共振

中文摘要 AI 辅助

基于局域洛伦兹模式与法布里-珀罗辐射连续谱之间相干干涉的法诺共振已被广泛探索用于微波超材料传感器、滤波器和光子器件。然而，传统法诺超表面存在角分散和偏振相关的光谱变化，限制了其在动态照明下的鲁棒性。在此，我们提出一种带折叠启用的平带工程策略，以在具有2x2放大单元的正交排列H形金属谐振器的平面微波超表面中实现鲁棒法诺共振。放大单元诱导布里渊区折叠，在15.3 GHz附近产生几乎无色散的平带，具有抑制的动量依赖性和增强的光子限制。该平带态提供与法布里-珀罗辐射连续谱强耦合的高Q局域共振，产生稳定的不对称法诺响应。此外，正交谐振器配置支持两个偏振解耦的偶极模式，具有相当的激发效率，减少了偏振引起的光谱畸变。近场测量和模拟验证了局域平带特征，而远场实验证明了在0°至30°斜入射下法诺响应的稳定性，共振变化微小。开发了一个时间耦合模式理论模型，以定量描述不同照明条件下的法诺光谱演变。这项工作建立了通过平带介导的鲁棒微波法诺超表面路径，并为稳定谐振光子器件设计提供了一般策略。

英文摘要

Fano resonances based on coherent interference between localized Lorentz modes and Fabry-Perot radiation continua have been widely explored for microwave metamaterial sensors, filters, and photonic devices. However, conventional Fano metasurfaces suffer from angular dispersion and polarization-dependent spectral variations, limiting robustness under dynamic illumination. Here, we propose a band-folding-enabled flatband engineering strategy to realize robust Fano resonances in a planar microwave metasurface with a 2x2 enlarged cell of orthogonally arranged H-shaped metallic resonators. The enlarged cell induces Brillouin-zone folding, generating a nearly dispersionless flatband near 15.3 GHz with suppressed momentum dependence and enhanced photonic confinement. This flatband state provides a high-Q localized resonance strongly coupled to the FP radiation continuum, producing a stable asymmetric Fano response. Furthermore, the orthogonal resonator configuration supports two polarization-decoupled dipole modes with comparable excitation efficiency, reducing polarization-induced spectral distortion. Near-field measurements and simulations verify localized flatband features, while far-field experiments demonstrate stable Fano responses under oblique incidence from 0° to 30° with minor resonance variation. A temporal coupled-mode theory model is developed to quantitatively describe Fano spectral evolution under different illumination conditions. This work establishes a flatband-mediated route toward robust microwave Fano metasurfaces and offers a general strategy for stable resonant photonic device design.

发表机构

• Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences（中国科学院深圳先进技术研究院）
• The Hong Kong University of Science and Technology (Guangzhou)（香港科技大学（广州））

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