基于贵金属劈裂纳米环阵列的多重表面晶格共振

Multiple Surface Lattice Resonances Generated with Noble Metallic Split-RingResonator Arrays

基于贵金属纳米颗粒阵列的多重表面晶格共振能够在多个波段同时抑制体系的辐射损耗,提高共振品质因子,增大局域场强。提出一种采用贵金属劈裂纳米环阵列产生多重表面晶格共振的方法。由于劈裂纳米环磁偶极共振的等效偶极矩垂直于纸面,能够同时向平面的x和y方向散射电磁波,这使得磁偶极共振与两个正交方向上的瑞利异常产生耦合成为可能。计算结果表明,在劈裂纳米环构成的阵列结构中,磁偶极共振能够与两个周期方向上瑞利异常形成耦合,从而产生表面晶格共振。当阵列周期不同时,能够同时激起两个表面晶格共振;利用劈裂纳米环的电四极共振也可得到类似的光学响应。这些特性使得贵金属劈裂纳米环阵列在微纳光子器件的设计方面将具有重要的应用价值。

Multiple surface lattice resonances generated with noble metallic nanoparticle array can be used to suppress radiative losses around several spectral positions,enlarge the resonance quality factor,and enhance the localized near-field intensity.This study proposed a method to generate multiple surface lattice resonances with noble metallic split-ring resonator arrays.It shows that for the magnetic dipole resonance,the generated equivalent magnetic dipole is oriented perpendicular to the paper plane,and the scattering fields are propagating along xand y directions,which makes it possible to realize the coupling between the magnetic dipole mode and the Rayleigh anomaly along both directions.The calculation results indeed reveal that the coupling between the magnetic dipole mode and the Rayleigh anomaly leads to the formation of a sharp surface lattice resonance,and double surface lattice resonances are generated when the lattice spacing are different with each other.Furthermore,the similar optical response can be obtained with electric quadrupole resonance of the split-ring resonator.These properties make splitring resonator arrays promise for the design of micro/nano photonic devices.