Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu, 610054, China.
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
Nat Commun. 2023 May 17;14(1):2811. doi: 10.1038/s41467-023-38367-y.
Non-radiative bound states in the continuum (BICs) allow construction of resonant cavities with confined electromagnetic energy and high-quality (Q) factors. However, the sharp decay of the Q factor in the momentum space limits their usefulness for device applications. Here we demonstrate an approach to achieve sustainable ultrahigh Q factors by engineering Brillouin zone folding-induced BICs (BZF-BICs). All the guided modes are folded into the light cone through periodic perturbation that leads to the emergence of BZF-BICs possessing ultrahigh Q factors throughout the large, tunable momentum space. Unlike conventional BICs, BZF-BICs show perturbation-dependent dramatic enhancement of the Q factor in the entire momentum space and are robust against structural disorders. Our work provides a unique design path for BZF-BIC-based silicon metasurface cavities with extreme robustness against disorder while sustaining ultrahigh Q factors, offering potential applications in terahertz devices, nonlinear optics, quantum computing, and photonic integrated circuits.
非辐射束缚态在连续体中（BIC）允许构建具有受限电磁能量和高质量（Q）因子的共振腔。然而，在动量空间中 Q 因子的急剧衰减限制了它们在器件应用中的用途。在这里，我们通过工程布里渊区折叠诱导束缚态（BZF-BIC）展示了一种实现可持续超高 Q 因子的方法。通过周期性扰动将所有导模折叠到光锥中，从而产生具有超高 Q 因子的 BZF-BIC，这些 Q 因子在大的、可调谐的动量空间中都存在。与传统的 BIC 不同，BZF-BIC 在整个动量空间中表现出与微扰相关的 Q 因子的显著增强，并且对结构无序具有鲁棒性。我们的工作为基于 BZF-BIC 的硅亚波长表面腔提供了独特的设计路径，这种亚波长表面腔具有对无序的极端鲁棒性，同时保持超高 Q 因子，为太赫兹器件、非线性光学、量子计算和光子集成电路提供了潜在的应用。
