Chao Minghao, Liu Qingsong, Zhang Wenjing, Zhuang Lingyun, Song Guofeng
Opt Express. 2022 Aug 1;30(16):29258-29270. doi: 10.1364/OE.457274.
Recently, high-order topological photonic crystals (PhCs) have attracted huge research attention due to their novel physics mechanism and the application potential in integrated photonics. Based on the two-dimensional Su-Schrieffer-Heeger model, we construct and study the mutual coupling between the high-order corner states in 2D dielectric PhCs. Simulation results show that the Q-factor of such corner-localized quasi-bound states in the continuum (BICs) could be enhanced following mutual coupling in finite size. Furthermore, we study the side-coupled structure based on defect-hybrid waveguides and the edge state microring, the quasi-BIC microcavity. The refractive index sensing application based on corner-localized quasi-BICs shows outstanding simulated sensitivity (312.8 nm/RIU) and figure of merit (∼10 1/RIU). The robustness against fabrication errors due to its topologically protected nature makes it competitive compared with other quasi-BICs sensors.
近年来，高阶拓扑光子晶体（PhCs）因其新颖的物理机制和在集成光子学中的应用潜力而备受研究关注。基于二维Su-Schrieffer-Heeger模型，我们构建并研究了二维介电光子晶体中高阶角态之间的相互耦合。模拟结果表明，在有限尺寸下通过相互耦合，连续统中此类角局域准束缚态（BICs）的品质因数可以得到提高。此外，我们研究了基于缺陷混合波导和边缘态微环的边耦合结构，即准BIC微腔。基于角局域准BICs的折射率传感应用显示出出色的模拟灵敏度（312.8 nm/RIU）和品质因数（约10 1/RIU）。由于其拓扑保护性质，对制造误差具有鲁棒性，这使其与其他准BICs传感器相比具有竞争力。
