Lin Jing, Qiu Meng, Zhang Xiyue, Guo Huijie, Cai Qingnan, Xiao Shiyi, He Qiong, Zhou Lei
State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education) and Department of Physics, Fudan University, Shanghai, 200433 China.
Key Laboratory of Specialty Fiber Optics and Optical Access Networks, Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication, Shanghai Institute for Advanced Communication and Data Science, Shanghai University, Shanghai, 200444 China.
Light Sci Appl. 2020 Sep 8;9:158. doi: 10.1038/s41377-020-00386-5. eCollection 2020.
Coupled photonic systems exhibit intriguing optical responses attracting intensive attention, but available theoretical tools either cannot reveal the underlying physics or are empirical in nature. Here, we derive a rigorous theoretical framework from first principles (i.e., Maxwell's equations), with all parameters directly computable via wave function integrations, to study coupled photonic systems containing multiple resonators. Benchmark calculations against Mie theory reveal the physical meanings of the parameters defined in our theory and their mutual relations. After testing our theory numerically and experimentally on a realistic plasmonic system, we show how to utilize it to freely tailor the lineshape of a coupled system, involving two plasmonic resonators exhibiting arbitrary radiative losses, particularly how to create a completely "dark" mode with vanishing radiative loss (e.g., a bound state in continuum). All theoretical predictions are quantitatively verified by our experiments at near-infrared frequencies. Our results not only help understand the profound physics in such coupled photonic systems, but also offer a powerful tool for fast designing functional devices to meet diversified application requests.
耦合光子系统展现出引人入胜的光学响应，吸引了广泛关注，但现有的理论工具要么无法揭示其潜在物理机制，要么本质上是经验性的。在此，我们从第一原理（即麦克斯韦方程组）推导出一个严格的理论框架，其中所有参数都可通过波函数积分直接计算得出，用于研究包含多个谐振器的耦合光子系统。与米氏理论的基准计算揭示了我们理论中定义的参数的物理意义及其相互关系。在一个实际的等离子体系统上进行数值和实验测试后，我们展示了如何利用该理论自由定制耦合系统的线形，该耦合系统涉及两个具有任意辐射损耗的等离子体谐振器，特别是如何创建一个具有零辐射损耗的完全“暗”模式（例如，连续统中的束缚态）。我们在近红外频率下的实验对所有理论预测进行了定量验证。我们的结果不仅有助于理解此类耦合光子系统中的深刻物理，还为快速设计满足多样化应用需求的功能器件提供了一个强大的工具。
