CEMES, CNRS, Université Paul Sabatier, 29 rue Jeanne Marvig, Toulouse 31055, France.
J Chem Phys. 2009 Dec 14;131(22):224707. doi: 10.1063/1.3271794.
Plasmonic structures are commonly used to both confine and enhance surface electromagnetic fields. In the past ten years, their peculiar optical properties have given rise to many promising applications ranging from high density data storage to surface optical trapping. In this context, we investigated both far-field and near-field optical response of a collection of densely packed silver nanocolumns embedded in amorphous aluminum oxide using the discrete dipole approximation. In the far field, a good fit of the calculated to the experimental absorption spectra can only be achieved when in addition to interaction between neighboring nanocolumns, a nanorod shape with periodic shrinks mimicking the experimental morphology of the nanocolumns is used. In the near field, modulated field intensities following the nanocolumns distribution and tunable with the incident wavelength are predicted outside the region occupied by the nanocolumns. This plasmonic image transfer has a resolution of approximately 1.8D where D is the diameter of the nanocolumns that in our case is 2.4 nm.
等离子体结构通常用于限制和增强表面电磁场。在过去的十年中，它们独特的光学性质带来了许多有前途的应用，从高密度数据存储到表面光阱。在这种情况下，我们使用离散偶极子近似法研究了嵌入非晶氧化铝中的密集银纳米柱的远场和近场光学响应。在远场中，只有当除了相邻纳米柱之间的相互作用之外，还使用周期性收缩的纳米棒形状来模拟纳米柱的实验形态时，才能很好地拟合计算的吸收光谱与实验的吸收光谱。在近场中，在纳米柱占据的区域之外，预测到了随纳米柱分布而变化并随入射波长可调的调制场强度。这种等离子体图像转移的分辨率约为 1.8D，其中 D 是纳米柱的直径，在我们的情况下为 2.4nm。
