近日，香港大学的张霜及其研究小组与香港科技大学的陈子亭等人合作并取得一项新进展。经过不懈努力，他们对拓扑光子晶体中的磁可控多模干涉进行研究。相关 研究成果已于2024年5月14日在国际知名学术期刊《光：科学与应用》上发表。

在这项工作中，研究人员展示了基于旋磁拓扑光子绝缘体的磁可控多模干涉，该绝缘体支持两种具有不同色散的单向边缘模式。在实验中，研究人员通过调节磁场强度或波的频率来设计多模干涉，成功实现了可控的功率分裂。这项研究工作表明，控制多个手性边缘模式之间的干涉可以促进高效和自适应微波器件的发展。

据悉，拓扑光子绝缘体在紧凑的集成光子电路中具有广阔的应用前景，主要得益于它们能够顺畅地通过尖锐弯曲来传输光。拓扑边缘状态的数量是基于边界上体积陈数之间的差异而定的，这一特性由体积与边缘之间的对应关系所决定。此外，拓扑光子学系统中多个拓扑边缘模式之间的干涉效应可实现可控的功能，这对于构建可重构光子器件特别理想。

附：英文原文

Title: Magnetically controllable multimode interference in topological photonic crystals

Author: Tang, Weiyuan, Wang, Mudi, Ma, Shaojie, Chan, Che Ting, Zhang, Shuang

Issue&Volume: 2024-05-14

Abstract: Topological photonic insulators show promise for applications in compact integrated photonic circuits due to their ability to transport light robustly through sharp bendings. The number of topological edge states relies on the difference between the bulk Chern numbers across the boundary, as dictated by the bulk edge correspondence. The interference among multiple topological edge modes in topological photonics systems may allow for controllable functionalities that are particularly desirable for constructing reconfigurable photonic devices. In this work, we demonstrate magnetically controllable multimode interference based on gyromagnetic topological photonic insulators that support two unidirectional edge modes with different dispersions. We successfully achieve controllable power splitting in experiments by engineering multimode interference with the magnetic field intensity or the frequency of wave. Our work demonstrates that manipulating the interference among multiple chiral edge modes can facilitate the advancement of highly efficient and adaptable microwave devices.

DOI: 10.1038/s41377-024-01433-1

Source: https://www.nature.com/articles/s41377-024-01433-1