Fizeau drag in graphene plasmonics
Fizeau drag in graphene plasmonics
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DOI：
10.1038/s41586-021-03640-x
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发表时间：
2021-06-24
期刊：
影响因子：
64.8
通讯作者：
Basov, D. N.
中科院分区：
文献类型：
--
作者：
Dong, Y.;Xiong, L.;Basov, D. N.
移动介质对光的拖曳由菲涅耳（1）预测，并由斐索著名的流动水实验（2）证实。这一重大发现是爱因斯坦狭义相对论的实验基石之一，并且在相对论运动学的背景下得到了很好的理解（3，4）。相比之下，固体中电子流拖动光子的实验充满了不一致性，迄今为止还没有与理论（5-7）达成一致。在这里，我们报告的电子流拖动表面等离子体激元（8，9）（SPPs）：混合准粒子的红外光子和电子在石墨烯。在高密度电流的存在下，通过传播等离子体波的红外纳米成像直接可视化阻力。石墨烯中的极化激元在对着漂移载流子传播时缩短了它们的波长。与光的斐索效应不同，电流引起的SPP阻力无法用简单的运动学来解释，而是与石墨烯中狄拉克电子的非线性电动力学有关。所观察到的等离子体Fizeau拖曳使得能够在红外频率下打破时间反演对称性和互易性（10），而无需求助于磁场（11，12）或手性光泵浦（13，14）。斐索拖曳也提供了一个工具，研究电子液体中的相互作用和非平衡效应。
Dragging of light by moving media was predicted by Fresnel(1) and verified by Fizeau's celebrated experiments(2) with flowing water. This momentous discovery is among the experimental cornerstones of Einstein's special relativity theory and is well understood(3,4) in the context of relativistic kinematics. By contrast, experiments on dragging photons by an electron flow in solids are riddled with inconsistencies and have so far eluded agreement with the theory(5-7). Here we report on the electron flow dragging surface plasmon polaritons(8,9) (SPPs): hybrid quasiparticles of infrared photons and electrons in graphene. The drag is visualized directly through infrared nano-imaging of propagating plasmonic waves in the presence of a high-density current. The polaritons in graphene shorten their wavelength when propagating against the drifting carriers. Unlike the Fizeau effect for light, the SPP drag by electrical currents defies explanation by simple kinematics and is linked to the nonlinear electrodynamics of Dirac electrons in graphene. The observed plasmonic Fizeau drag enables breaking of time-reversal symmetry and reciprocity(10) at infrared frequencies without resorting to magnetic fields(11,12) or chiral optical pumping(13,14). The Fizeau drag also provides a tool with which to study interactions and nonequilibrium effects in electron liquids.