Department of Electrical, Computer and Energy Engineering, University of Colorado Boulder, Boulder, Colorado 80309-0425, USA.
Nanoscale. 2013 Feb 21;5(4):1592-602. doi: 10.1039/c2nr33292b.
We present orientation dependence and tuning of Fano resonances in plasmonic gold nanorod heptamer nanostructures. The heptamer structures were formed by surrounding a central circular nanoparticle by six satellite nanorods in a hexagonal arrangement and the heptamer structures were then embedded in a thin flexible membrane. The Fano resonance was found to depend on the orientation of the nanorods within the heptamer and for a given orientation, the Fano resonance was dynamically tuned and its symmetry lowered by application of uniaxial mechanical stress. The expected spectral features were obtained by simulations and verified by experiments. The spectral features of the heptamer structures were further characterized by using detailed group theoretical analysis. We show that both sub-structural and mechanical tuning could be employed to engineer the Fano resonances in complex plasmonic molecules.
我们展示了在等离子体金纳米棒七聚体纳米结构中存在的各向异性的 Fano 共振及其调谐。七聚体结构是通过在一个中心的圆形纳米粒子周围放置六个呈六边形排列的卫星纳米棒而形成的，然后将七聚体结构嵌入在一个薄的柔性膜中。发现 Fano 共振取决于纳米棒在七聚体中的取向，并且对于给定的取向，通过施加单轴机械应力，可以动态地调谐 Fano 共振，并且降低其对称性。通过模拟得到了预期的光谱特征，并通过实验进行了验证。通过详细的群论分析进一步表征了七聚体结构的光谱特征。我们表明，亚结构和机械调谐都可以用来设计复杂等离子体分子中的 Fano 共振。
