Department of Physics, University of California at Berkeley , Berkeley, California 94720, United States.
Materials Science Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
Nano Lett. 2017 Jun 14;17(6):3662-3667. doi: 10.1021/acs.nanolett.7b00845. Epub 2017 May 3.
Surface plasmons (SPs) and phonon polaritons (PhPs) are two distinctive quasiparticles resulting from the strong coupling of photons with electrons and optical phonons, respectively. In this Letter, we investigate the interactions between one-dimensional (1D) plasmons in silver nanowires with two-dimensional (2D) surface phonon polaritons of the silicon carbide (SiC) substrate. Using near-field infrared spectroscopy of the silver nanowire-SiC heterostructure at wavelengths close to the phonon resonance of SiC, we observe that the 1D plasmon dispersion is strongly modified by the 2D phonon polaritons in SiC. In particular, we observe for the first time well-defined 1D plasmon oscillations with the plasmon wavelengths longer than the free-space photon wavelengths due to the 1D plasmon-2D phonon polariton coupling. Our work demonstrates that unusual polariton behavior can emerge from interactions between polariton excitons of different dimensionality, which can enable new ways to engineer plasmons in hybrid structures.
表面等离激元（SPs）和声子极化激元（PhPs）是两种独特的准粒子，分别是由光子与电子以及光学声子的强耦合产生的。在这篇快报中，我们研究了银纳米线中的一维（1D）等离激元与碳化硅（SiC）衬底的二维（2D）表面声子极化激元之间的相互作用。我们利用银纳米线-SiC 异质结构在接近 SiC 声子共振波长的近场红外光谱，观察到 2D 声子极化激元强烈地改变了 SiC 中的 1D 等离激元色散。特别是，我们首次观察到由于 1D 等离激元-2D 声子极化激元耦合，在自由空间光子波长以上的具有明确 1D 等离激元振荡的现象。我们的工作表明，不同维度的极化激元激子之间的相互作用可以产生不同寻常的极化激元行为，这可以为混合结构中的等离激元工程提供新的途径。
