Kullock René, Hendren William R, Hille Andreas, Grafström Stefan, Evans Paul R, Pollard Robert J, Atkinson Ron, Eng Lukas M
Institute of Applied Photophysics, Technische Universität Dresden, 01062 Dresden, Germany.
Opt Express. 2008 Dec 22;16(26):21671-81. doi: 10.1364/oe.16.021671.
For two-dimensional (2D) arrays of metallic nanorods arranged perpendicular to a substrate several methods have been proposed to determine the electromagnetic near-field distribution and the surface plasmon resonances, but an analytical approach to explain all optical features on the nanometer length scale has been missing to date. To fill this gap, we demonstrate here that the field distribution in such arrays can be understood on the basis of surface plasmon polaritons (SPPs) that propagate along the nanorods and form standing waves. Notably, SPPs couple laterally through their optical near fields, giving rise to collective surface plasmon (CSP) effects. Using the dispersion relation of such CSPs, we deduce the condition of standing-wave formation, which enables us to successfully predict several features, such as eigenmodes and resonances. As one such property and potential application, we show both theoretically and in an experiment that CSP propagation allows for polarization conversion and optical filtering in 2D nanorod arrays. Hence, these arrays are promising candidates for manipulating the light polarization on the nanometer length scale.
对于垂直排列在衬底上的金属纳米棒二维（2D）阵列，已经提出了几种方法来确定电磁近场分布和表面等离子体共振，但迄今为止，还缺少一种能在纳米长度尺度上解释所有光学特征的分析方法。为了填补这一空白，我们在此证明，这种阵列中的场分布可以基于沿纳米棒传播并形成驻波的表面等离子体激元（SPP）来理解。值得注意的是，SPP通过其光学近场进行横向耦合，从而产生集体表面等离子体（CSP）效应。利用这种CSP的色散关系，我们推导出了驻波形成的条件，这使我们能够成功预测几个特征，如本征模和共振。作为这样一种特性和潜在应用，我们在理论和实验上都表明，CSP传播允许在二维纳米棒阵列中进行偏振转换和光学滤波。因此，这些阵列有望成为在纳米长度尺度上操纵光偏振的候选材料。
