Topological Valley Photonics: Physics and Device Applications

• Published in: Advanced photonics research Vol. 2; no. 8
• Main Authors: Xue, Haoran, Yang, Yihao, Zhang, Baile
• Format: Journal Article
• Language: English
• Published: Hoboken John Wiley & Sons, Inc 01.08.2021; Wiley-VCH
• Subjects: Communication; Crystals; Energy; Graphene; Information storage; Onsite; Photonics; Physics; Semiconductors; Symmetry; topological photonics; valley photonic crystals; valley-Hall phases
• ISSN: 2699-9293; 2699-9293
• DOI: 10.1002/adpr.202100013

Topological photonics has emerged as a promising field in photonics that is able to shape the science and technology of light. As a significant degree of freedom, valley is introduced to design and construct photonic topological phases, with encouraging recent progress in applications ranging from on‐chip communications to terahertz lasers. Herein, the development of topological valley photonics is reviewed, from both perspectives of fundamental physics and practical applications. The unique valley‐contrasting physics determines that the bulk topology and the bulk‐boundary correspondence in valley photonic topological phases exhibit different properties from other photonic topological phases. Valley conservation allows not only robust propagation of light through sharp corners, but also 100% out‐coupling of topological states to the surrounding environment. Finally, robust valley transport requires no magnetic materials or the complex construction of photonic pseudospin and, thus, can be integrated on compact photonic platforms for future technologies. Topological photonics offers new possibilities to manipulate light in robust manners. Among different photonic topological phases, photonic valley‐Hall phase is quite promising for future technologies due to its simple design and excellent performance. This article reviews the developments in studying topological valley photonics, which covers both fundamental physics and device applications.