Yang Yuting, Qian Xinyue, Shi Liwei, Shen Xiaopeng, Wang Yifan, Hang Zhi Hong
Opt Express. 2022 Feb 14;30(4):5731-5738. doi: 10.1364/OE.440108.
Finite-size effect plays a significant role in topology photonics not to mention in reality all experimental setups are in finite-size. A photonic bandgap is opened in the topological edge state dispersion if a topological photonic crystal with finite width is considered, and the bandgap size relies on the finite-size effect. Pseudospin-preserving and pseudospin-flipping processes can be realized when a selectively switch of the pseudospin of edge states are customized by our designs. Our microwave experiments also successfully demonstrate pseudospin switch-on and -off behaviors in a finite-width photonic crystal. By combining photonic crystals with finite widths, a multi-tunneling proposal of topological photonic crystals can also be achieved. Our study of the finite-size effect will provide new approaches and thoughts to improve the development of topological photonic devices in the future.
有限尺寸效应在拓扑光子学中起着重要作用，更何况在现实中所有实验装置都是有限尺寸的。如果考虑具有有限宽度的拓扑光子晶体，在拓扑边缘态色散中会打开一个光子带隙，并且带隙大小依赖于有限尺寸效应。当通过我们的设计定制边缘态赝自旋的选择性切换时，可以实现赝自旋保持和赝自旋翻转过程。我们的微波实验也成功地证明了在有限宽度光子晶体中的赝自旋开启和关闭行为。通过结合具有有限宽度的光子晶体，还可以实现拓扑光子晶体的多隧穿方案。我们对有限尺寸效应的研究将为未来改进拓扑光子器件的发展提供新的方法和思路。
