Pakeltis Grace, Rotunno Enzo, Khorassani Siamak, Garfinkel David A, Collette Robyn, West Claire A, Retterer Scott T, Idrobo Juan Carlos, Masiello David J, Rack Philip D
Opt Express. 2021 Feb 1;29(3):4661-4671. doi: 10.1364/OE.416046.
We leverage the high spatial and energy resolution of monochromated aberration-corrected scanning transmission electron microscopy to study the hybridization of cyclic assemblies of plasmonic gold nanorods. Detailed experiments and simulations elucidate the hybridization of the coupled long-axis dipole modes into collective magnetic and electric dipole plasmon resonances. We resolve the magnetic dipole mode in these closed loop oligomers with electron energy loss spectroscopy and confirm the mode assignment with its characteristic spectrum image. The energy splitting of the magnetic mode and antibonding modes increases with the number of polygon edges (n). For the n=3-6 oligomers studied, optical simulations using normal incidence and s-polarized oblique incidence show the respective electric and magnetic modes' extinction efficiencies are maximized in the n=4 arrangement.
我们利用单色像差校正扫描透射电子显微镜的高空间和能量分辨率来研究等离子体金纳米棒循环组装体的杂交情况。详细的实验和模拟阐明了耦合长轴偶极子模式杂交形成集体磁偶极子和电偶极子等离子体共振的过程。我们通过电子能量损失谱分辨出这些闭环低聚物中的磁偶极子模式，并利用其特征光谱图像确认了模式归属。磁模式和反键模式的能量分裂随多边形边数（n）增加。对于所研究的n = 3 - 6低聚物，使用正入射和s偏振斜入射的光学模拟表明，在n = 4排列中，相应的电模式和磁模式的消光效率达到最大值。
