Department of Physics, University of California San Diego, La Jolla, California 92093, United States.
Nano Lett. 2011 Nov 9;11(11):4701-5. doi: 10.1021/nl202362d. Epub 2011 Oct 12.
We report on infrared (IR) nanoscopy of 2D plasmon excitations of Dirac fermions in graphene. This is achieved by confining mid-IR radiation at the apex of a nanoscale tip: an approach yielding 2 orders of magnitude increase in the value of in-plane component of incident wavevector q compared to free space propagation. At these high wavevectors, the Dirac plasmon is found to dramatically enhance the near-field interaction with mid-IR surface phonons of SiO(2) substrate. Our data augmented by detailed modeling establish graphene as a new medium supporting plasmonic effects that can be controlled by gate voltage.
我们报告了在狄拉克费米子的二维等离激元激发的中红外（IR）纳米光谱学。这是通过将中红外辐射限制在纳米级尖端的顶点来实现的：与自由空间传播相比，这种方法使入射波矢 q 的平面分量的值增加了两个数量级。在这些高波矢下，发现狄拉克等离激元极大地增强了与 SiO2 衬底的中红外表面声子的近场相互作用。我们的数据通过详细的建模得到了增强，确定了石墨烯作为一种新的支持等离子体效应的介质，该效应可以通过栅极电压来控制。
