Graphene and its relatives, such as bilayer and trilayer graphene, are promising plasmonic materials. Very recently, graphene has been demonstrated to be precisely folded (Chen et al 2019 Science 365 1036–40), thus folded graphene provides another appealing platform for plasmonics. In folded graphene nanodisks, we find fundamental dipole modes (DMs) will exhibit mode splitting, with one parallel and another perpendicular to the folding axis. The two DMs show differences in field patterns and folding angle dependence, but they both can be tuned by the size of structures and the Fermi level of graphene. Some interesting high order modes are introduced as well, which can be further engineered by folding. Our studies enrich the current research of graphene plasmonics, and pave the way for particular plasmonic device applications.

石墨烯及其类似物，例如双层和三层石墨烯，是很有前途的等离子体材料。最近，石墨烯被证明可以精确折叠（Chen et al 2019 Science 3651036–40），因此折叠后的石墨烯为等离子体技术提供了另一个诱人的平台。在折叠的石墨烯纳米盘中，我们发现基本偶极子模式（DMs）将表现出模式分裂，其中一个平行于折叠轴，另一个垂直于折叠轴。两种DM在场图和折叠角依赖性方面显示出差异，但它们均可通过结构尺寸和石墨烯的费米能级进行调整。还引入了一些有趣的高阶模式，可以通过折叠对其进行进一步设计。我们的研究丰富了石墨烯等离子技术的当前研究，并为特定的等离子设备应用铺平了道路。