Hybrid Plasmonic Cavity Modes in Arrays of Gold Nanotubes
Hybrid Plasmonic Cavity Modes in Arrays of Gold Nanotubes
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DOI：
10.1002/adom.201600731
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发表时间：
2017-02
影响因子：
9
通讯作者：
Junfeng Wang;C. Zhang;Junxi Zhang;Haojie Song;Pei Wang;Yonghua Lu;G. Fei;Wen Xu;Wei Xu
中科院分区：
文献类型：
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作者：
Junfeng Wang;C. Zhang;Junxi Zhang;Haojie Song;Pei Wang;Yonghua Lu;G. Fei;Wen Xu;Wei Xu
众所周知，等离子体结构将光限制在纳米尺度上，并且它们在小模式体积内显示出增强的电磁场。在这里，我们研究了一种由周期排列的金纳米管嵌入到阳极氧化铝中的超材料等离子体谐振器，并证明了低损耗的局域场具有很强的限制作用。观察到当纳米管长度超过某一临界值时，金纳米管中局域表面等离子体的高阶共振模式。数值模拟结果表明，长纳米管的一些高阶纵模和短管或薄壁纳米管的一些低阶纵模的电场主要以驻波纵模的形式集中在氧化铝和金的界面上，部分集中在纳米管的孔洞和两端，这是由于具有特殊光学传输效应的法布里-珀罗共振通过纳米管内部的纳米通道在周期性结构中的强耦合，从而使纳米管起到了有效的腔谐振子的作用。揭示了金纳米管超材料中由于横模和纵模的近场耦合而产生的电场分布不对称的混合等离子体共振腔模式的存在。
Plasmonic structures are known to confine light at the nanometer scale, and they exhibit enhanced electromagnetic fields localized in small mode volumes. Here, plasmonic resonators based on a metamaterial consisting of periodic arrays of gold nanotubes embedded into anodic aluminum oxide are studied and strong confinement of local fields with low losses is demonstrated. Higher‐order resonance modes of surface plasmons localized in gold nanotubes when the nanotube length exceeds some critical values are observed. The numerical simulations suggest that, the electric fields associated with some higher‐order longitudinal modes for the long nanotubes and some lower‐order longitudinal modes for the short nanotubes or the nanotubes with thin walls, are mainly localized at the interfaces between aluminum oxide and gold in the form of the standing‐wave longitudinal plasmonic modes, partially localized in the pores and at two ends of the nanotubes owing to the strong coupling of the Fabry–Pérot resonances with extraordinary optical transmission effect in the periodical structures through the inner nanochannels of the nanotubes, so that the nanotubes play a role of efficient cavity resonators. The existence of hybrid plasmonic resonant cavity modes with asymmetrical distributions of the electric field resulting from the near‐field coupling of both transversal and longitudinal modes in the gold nanotube metamaterials is revealed.