Institut de Ciències Fotòniques (ICFO)-The Institute of Photonic Sciences, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
Laboratoire Charles Coulomb (L2C), Université de Montpellier, CNRS, 34095 Montpellier Cedex, France.
Science. 2018 Apr 20;360(6386):291-295. doi: 10.1126/science.aar8438.
The ability to confine light into tiny spatial dimensions is important for applications such as microscopy, sensing, and nanoscale lasers. Although plasmons offer an appealing avenue to confine light, Landau damping in metals imposes a trade-off between optical field confinement and losses. We show that a graphene-insulator-metal heterostructure can overcome that trade-off, and demonstrate plasmon confinement down to the ultimate limit of the length scale of one atom. This is achieved through far-field excitation of plasmon modes squeezed into an atomically thin hexagonal boron nitride dielectric spacer between graphene and metal rods. A theoretical model that takes into account the nonlocal optical response of both graphene and metal is used to describe the results. These ultraconfined plasmonic modes, addressed with far-field light excitation, enable a route to new regimes of ultrastrong light-matter interactions.
将光限制在微小的空间尺寸内的能力对于显微镜、传感和纳米尺度激光等应用非常重要。尽管等离子体提供了一种有吸引力的限制光的途径，但金属中的 Landau 阻尼在光学场限制和损耗之间造成了权衡。我们表明，石墨烯-绝缘体-金属异质结构可以克服这种权衡，并将等离子体限制到一个原子尺度的极限。这是通过在石墨烯和金属棒之间的原子薄六方氮化硼介电间隔体中压缩的等离子体模式的远场激发来实现的。一个考虑到石墨烯和金属的非局域光响应的理论模型被用来描述结果。这些超受限的等离子体模式，通过远场光激发来实现，可以实现新的超强光物质相互作用的模式。
