Adjustable slow light with high group index in a graphene metasurface based on plasmon-induced transparency

• Published in: Diamond and related materials 2024-11, Vol.149, p.111520, Article 111520
• Main Authors: Hu, Yanchao, Zhang, Wenhao, Hu, Xiang, Li, Feng, Su, Wei, Wu, Hong
• Format: Article
• Language: English
• Subjects: Metasurface; Plasmon-induced transparency; Slow light
• ISSN: 0925-9635
• DOI: 10.1016/j.diamond.2024.111520

A relatively simple metasurface structure is proposed to achieve a dynamically tunable slow light effect. The metasurface consists of two horizontal graphene strips and two vertical continuous graphene strips. Strong interference between the bright and dark modes enables the metasurface to generate a significant triple plasmon-induced transparency (PIT). Varying the coupling distance between the horizontal strips, double-PIT and triple-PIT can be transformed into each other. During the reduction of the transparent window, electromagnetic waves undergo strong phase changes, resulting in a higher group index. After structural optimization, the maximum time delay and group index can be as high as 2.624 ps and 3934, surpassing comparable slow light devices. The proposed patterned graphene metasurface provides theoretical guidance for designing high-performance slow light devices for optical storage, nonlinear optics and quantum optics. [Display omitted] •Based on graphene strips for achieving triple plasmon-induced transparency (PIT) effect.•The PIT effect can be dynamically regulated by the Fermi levels of graphene.•Varying the coupling distance between the two horizontal graphene strips, the triple-PIT can evolve into a dual-PIT.•The proposed metasurface exhibits outstanding slow-light performance with a group index up to 3934.