Non-Hermitian topological light steering

• Published in: Science (American Association for the Advancement of Science) Vol. 365; no. 6458; pp. 1163 - 1166
• Main Authors: Zhao, Han, Qiao, Xingdu, Wu, Tianwei, Midya, Bikashkali, Longhi, Stefano, Feng, Liang
• Format: Journal Article
• Language: English
• Published: United States The American Association for the Advancement of Science 13-09-2019
• Subjects: Domains; Dynamic control; Light; Photonics; Propagation; Reconfiguration; Robust control; Robustness (mathematics); Routing; Steering; Topological insulators; Topology
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aay1064

Photonic topological insulators provide a route for disorder-immune light transport, which holds promise for practical applications. Flexible reconfiguration of topological light pathways can enable high-density photonics routing, thus sustaining the growing demand for data capacity. By strategically interfacing non-Hermitian and topological physics, we demonstrate arbitrary, robust light steering in reconfigurable non-Hermitian junctions, in which chiral topological states can propagate at an interface of the gain and loss domains. Our non-Hermitian-controlled topological state can enable the dynamic control of robust transmission links of light inside the bulk, fully using the entire footprint of a photonic topological insulator.