State Key Laboratory of Optoelectronic Materials and Technologies & School of Physics, Sun Yat-sen University, Guangzhou, 510275, China.
Nat Commun. 2019 Feb 20;10(1):872. doi: 10.1038/s41467-019-08881-z.
Backscattering suppression in silicon-on-insulator (SOI) is one of the central issues to reduce energy loss and signal distortion, enabling for capability improvement of modern information processing systems. Valley physics provides an intriguing way for robust information transfer and unidirectional coupling in topological nanophotonics. Here we realize topological transport in a SOI valley photonic crystal slab. Localized Berry curvature near zone corners guarantees the existence of valley-dependent edge states below light cone, maintaining in-plane robustness and light confinement simultaneously. Topologically robust transport at telecommunication is observed along two sharp-bend interfaces in subwavelength scale, showing flat-top high transmission of ~10% bandwidth. Topological photonic routing is achieved in a bearded-stack interface, due to unidirectional excitation of valley-chirality-locked edge state from the phase vortex of a nanoscale microdisk. These findings show the prototype of robustly integrated devices, and open a new door towards the observation of non-trivial states even in non-Hermitian systems.
在绝缘体上硅（SOI）中抑制背向散射是降低能量损失和信号失真的核心问题之一，使现代信息处理系统的性能得到提高。谷物理为拓扑纳米光子学中的稳健信息传输和单向耦合提供了一种有趣的方法。在这里，我们在 SOI 谷光子晶体平板中实现了拓扑传输。近区角处的局域贝里曲率保证了光锥以下存在谷依赖的边缘态，同时保持了平面内的稳健性和光限制。在电信波段观察到拓扑稳健传输，其沿着亚波长尺度的两个急转弯界面进行，显示出约 10%带宽的平顶高透射率。在胡须堆叠界面中实现了拓扑光子路由，这是由于纳米级微盘的相位涡旋从谷手性锁定的边缘态中单向激发。这些发现展示了稳健集成器件的原型，并为观察非平凡态甚至在非厄米系统中开辟了新的途径。
