标题： 等离子体纳米颗粒阵列中的电四极矩和磁偶极矩耦合 显示英文标题

标题： Electric quadrupole and magnetic dipole coupling in plasmonic nanoparticle arrays

摘要： 在电偶极矩沿晶格波传播方向排列的等离激元纳米颗粒阵列中的集体共振现象进行了理论研究。 金纳米颗粒的电四极矩（EQ）和磁偶极矩（MD）在阵列的共振特性中的作用进行了分析。 我们进行了半解析的耦合多极方程计算和严格的数值模拟，通过改变颗粒尺寸和形状（球体和圆盘）来调整电和磁多极的贡献。 考虑了均匀和非均匀环境中的阵列。 我们发现，单个颗粒的即使非常微弱的非共振 EQ 和 MD 矩，在集体（晶格）共振激发波长处的周期性晶格中也会显著增强。 重要的是，我们表明在无限阵列中，纳米颗粒的 EQ 和 MD 矩相互耦合，并影响彼此的共振贡献。 我们还证明，在晶格共振波长处，增强的 EQ 和 MD 矩对反射的贡献与偶极子的一样大，从而显著降低反射，并满足反射抑制的广义 Kerker 条件。 显示英文摘要

摘要： Collective resonances in plasmonic nanoparticle arrays with electric dipole moment oriented along the lattice wave propagation are theoretically investigated. The role of electric quadrupole (EQ) and magnetic dipole (MD) moments of gold nanoparticles in the resonant features of the arrays is analyzed. We perform both semi-analytical calculations of coupled multipole equations and rigorous numerical simulations varying contributions of the electric and magnetic multipoles by changing particle size and shape (spheres and disks). The arrays in homogeneous and non-homogeneous environments are considered. We find that even very weak non-resonant EQ and MD moments of a single particle are significantly enhanced in the periodic lattice at the wavelength of collective (lattice) resonance excitation. Importantly, we show that in the infinite arrays, the EQ and MD moments of nanoparticles are coupled and affect each other resonant contributions. We also demonstrate that at the lattice-resonance wavelength, the enhanced EQ and MD moments have contributions to reflection comparable to the dipole one resulting in a significant decrease of reflection and providing the satisfaction of the generalized Kerker condition for reflection suppression.