Zhang Z Y, Li D M, Zhang H, Wang W, Zhu Y H, Zhang S, Zhang X P, Yi J M
Opt Express. 2019 Apr 29;27(9):13503-13515. doi: 10.1364/OE.27.013503.
Integrating gate-tunable graphene with plasmonic nanostructures or metamaterials offers a great potential in achieving dynamic control of plasmonic response. While remarkable progress has been made in realizing efficient graphene-induced modulations of plasmon resonances, a full picture of graphene-plasmon interactions and the consequent deep understanding on graphene-enabled tuning mechanism remain largely unexplored. Here, we theoretically identify, for the first time, two distinct modulation effects that can coexist in graphene-based plasmonic nanostructure: graphene can influence the plasmon resonances by either acting as equivalent nanocircuit elements or effectively altering their excitation environment, leading to totally different tuning behaviors. A general dependency of tuning features on the graphene-induced impedance, irrespective of structure geometries, is established when graphene serves as nanocircuit elements. We demonstrate that these two modulation effects can be dynamically controlled by appropriately integrating graphene with plasmonic nanostructures, which provide an active window for efficient modulation of surface plasmons. Our findings may pave the way towards realizing dynamic control of plasmonic response, which holds great potential applications in graphene-based active nanoplasmonic devices.
将栅极可调谐石墨烯与等离子体纳米结构或超材料相结合，在实现等离子体响应的动态控制方面具有巨大潜力。虽然在实现高效的石墨烯诱导的等离子体共振调制方面已经取得了显著进展，但石墨烯与等离子体相互作用的全貌以及对基于石墨烯的调谐机制的深入理解在很大程度上仍未得到探索。在这里，我们首次从理论上确定了两种不同的调制效应，它们可以共存于基于石墨烯的等离子体纳米结构中：石墨烯既可以作为等效的纳米电路元件来影响等离子体共振，也可以有效地改变它们的激发环境，从而导致完全不同的调谐行为。当石墨烯作为纳米电路元件时，无论结构几何形状如何，调谐特性都普遍依赖于石墨烯诱导的阻抗。我们证明，通过将石墨烯与等离子体纳米结构适当结合，可以动态控制这两种调制效应，这为高效调制表面等离子体提供了一个活跃窗口。我们的发现可能为实现等离子体响应的动态控制铺平道路，这在基于石墨烯的有源纳米等离子体器件中具有巨大的潜在应用。
