From plasmonic nanoantennas to split-ring resonators: tuning scattering strength
From plasmonic nanoantennas to split-ring resonators: tuning scattering strength
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DOI：
10.1364/josab.27.001680
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发表时间：
2010-08
影响因子：
1.9
通讯作者：
A. Pors;M. Willatzen;O. Albrektsen;S. Bozhevolnyi
中科院分区：
文献类型：
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作者：
A. Pors;M. Willatzen;O. Albrektsen;S. Bozhevolnyi
被认为是由弯曲的直的金纳米棒天线转换到开口环谐振器的三维延迟为基础的等离子体共振器的吸收和散射截面，质量因子（Q因子），和场增强的演变。的光学共振被证实是等离子体起源，并具体示出了由直的和弯曲的纳米棒支持的短程表面等离子体极化激元的驻波的形成有关。我们验证了，通过弯曲纳米天线，可以减少并最终在开口环谐振器的限制下，实际上消除它们在基本谐振处的散射，从而导致相应的Q因子大幅增加。弯曲引起的散射减少与电偶极子响应的衰减有关，有利于磁偶极子响应，导致Q因子超过准静态极限1.7倍。同时，该结构表现出>50的局部场增强。
Evolution of the absorption and scattering cross sections, quality-factor (Q-factor), and field enhancement of three-dimensional retardation-based plasmonic resonators being transformed from straight gold nanorod antennas to split-ring resonators by bending is considered. The optical resonances are confirmed to be of plasmonic origin and are specifically shown to be related to the formation of standing waves of short-range surface plasmon polaritons supported by straight and bent nanorods. We verify that by bending nanoantennas it is possible to reduce and ultimately, in the split-ring resonator limit, practically eliminate their scattering at the fundamental resonance, resulting in a substantial increase in the corresponding Q-factors. The decrease in scattering by bending is connected with the attenuation of the electric-dipole response in favor of a magnetic-dipole one, leading to Q-factors exceeding the quasi-static limit by a factor of ∼1.7. Simultaneously, the structures exhibit local field enhancements of >50.