Photonic Systems Laboratory, Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea.
Sci Rep. 2017 Feb 27;7:43333. doi: 10.1038/srep43333.
Graphene plasmonics has become a highlighted research area due to the outstanding properties of deep-subwavelength plasmon excitation, long relaxation time, and electro-optical tunability. Although the giant conductivity of a graphene layer enables the low-dimensional confinement of light, the atomic scale of the layer thickness is severely mismatched with optical mode sizes, which impedes the efficient tuning of graphene plasmon modes from the degraded light-graphene overlap. Inspired by gap plasmon modes in noble metals, here we propose low-dimensional hybrid graphene gap plasmon waves for large light-graphene overlap factor. We show that gap plasmon waves exhibit improved in-plane and out-of-plane field concentrations on graphene compared to those of edge or wire-like graphene plasmons. By adjusting the chemical property of the graphene layer, efficient and linear modulation of hybrid graphene gap plasmon modes is also achieved. Our results provide potential opportunities to low-dimensional graphene plasmonic devices with strong tunability.
由于深亚波长等离子体激元激发、长弛豫时间和电光可调谐性等优异性能，石墨烯等离子体激元学已成为一个备受关注的研究领域。尽管石墨烯层的巨大电导率能够实现光的低维限制，但层厚度的原子尺度与光学模式尺寸严重不匹配，这阻碍了从降低的光-石墨烯重叠中有效地调谐石墨烯等离子体模式。受贵金属中的间隙等离子体模式的启发，我们在这里提出了低维混合石墨烯间隙等离子体波，以实现大的光-石墨烯重叠因子。我们表明，与边缘或线状石墨烯等离子体相比，间隙等离子体波在石墨烯上表现出更好的面内和面外场浓度。通过调整石墨烯层的化学性质，还实现了混合石墨烯间隙等离子体模式的高效和线性调制。我们的结果为具有强可调性的低维石墨烯等离子体器件提供了潜在的机会。
