标题： 基于连续谱中传播束缚态的纤维 显示英文标题

标题： Fibers based on propagating bound states in the continuum

摘要： 我们证明，一个由$N$介质圆柱组成的周期性环形阵列支持沿圆柱传播的几乎连续态束缚态（BICs）。这些具有极高$Q$因子的传播几乎BICs，其数量级为$exp(\lambda N)$，被弱泄漏到辐射连续体中的共振模式所包围。我们展示了不同类型的BIC附近泄漏区域：具有对称性保护的几乎BICs，其共振宽度与传播常数的平方$\Gamma \sim k_z^2$成比例；非对称性保护的几乎BICs，其传播常数为有限值$k_c$且有$\Gamma\sim (k_z-k_c)^2$；以及非对称性保护的几乎BICs，其具有$\Gamma\sim k_z^4$。后者传播的几乎BICs可用于电磁信号传输，为新型光纤开辟了道路。我们还展示了携带轨道角动量的弱泄漏共振模式。 显示英文摘要

摘要： We show that a circular periodic array of $N$ dielectric cylinders supports nearly bound states in the continuum (BICs) propagating along the cylinders. These propagating nearly BICs with extremely large $Q$ factors of order $exp(\lambda N)$ are surrounded by resonant modes weakly leaking into the radiation continuum. We present leaky zones in the vicinity of different types of BICs: symmetry protected nearly BICs with the resonant width proportional to the squared propagation constant $\Gamma \sim k_z^2$, non-symmetry protected nearly BICs with finite propagation constant $k_c$ with $\Gamma\sim (k_z-k_c)^2$ and non-symmetry protected nearly BICs with $\Gamma\sim k_z^4$. The latter propagating nearly BICs can serve for transmission of electromagnetic signal paving a way to novel type of optical fibers. We also demonstrate weakly leaking resonant modes which carry orbital angular momentum.