Opt Lett. 2018 Jul 1;43(13):3053-3056. doi: 10.1364/OL.43.003053.
Huygens' nanoantennas maintain orthogonal electric and magnetic dipole resonances satisfying the Kerker condition and can generate directional radiation in both the near-field and far-field regimes. Here we study a multilayered metal-dielectric-metal (MDM) Huygens' type nanoantenna which is capable of launching surface plasmon polaritons (SPPs) unidirectionally when excited by a dipole source. We show that the radiative decay rates of the dipole source are strongly enhanced by the antenna, and the generated SPP waves propagate in opposite directions at two different wavelengths. The directionality of the excited SPPs can be switched by changing the geometry and the material composition. We further demonstrated that the beam width of the SPP waves can be narrowed by arranging the MDM antennas in a chain.
惠更斯纳米天线保持正交的电偶极子和磁偶极子共振，满足 Kerker 条件，并可以在近场和远场区域产生定向辐射。在这里，我们研究了一种多层金属-电介质-金属（MDM）惠更斯型纳米天线，当由偶极子源激发时，它能够单向发射表面等离激元（SPP）。我们表明，天线强烈增强了偶极子源的辐射衰减率，并且生成的 SPP 波在两个不同的波长以相反的方向传播。通过改变几何形状和材料组成，可以切换激发 SPP 的方向性。我们进一步证明，通过将 MDM 天线排列成链，可以缩小 SPP 波的波束宽度。
