Visualization of Near-Field Enhancements of Gold Triangles by Nonlinear Photopolymerization
Visualization of Near-Field Enhancements of Gold Triangles by Nonlinear Photopolymerization
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DOI：
10.1007/s11468-010-9189-9
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发表时间：
2011-06-01
期刊：
影响因子：
3
通讯作者：
Misawa, Hiroaki
中科院分区：
文献类型：
--
作者：
Geldhauser, Tobias;Ikegaya, Shintarou;Misawa, Hiroaki
本文用双光子聚合的方法报道了偶极子和四极子等离激元模式下金三角形阵列的近场分布。为了将三角阵时域有限差分模拟与实验结果联系起来，给出了两种情况下的消光谱图。对于边长为85 nm、厚度为40 nm的金三角形，计算得到的激发偶极子模近场沿激发激光束偏振方向的分布与实验结果一致。对于边长为540 nm的较大三角形，激发四极子模式，导致光束偏振方向的近场分布旋转90A度。FDTD仿真也显示了这种效应。
We report in this paper the near-field distribution in the case of gold triangle arrays by means of two-photon polymerization for a dipole and a quadrupole plasmon mode. In order to link the finite difference in the time domain (FDTD) simulations of the triangle array and the experimental results, extinction spectra for both cases in air and SU-8 environments are shown. In case of the 40-nm thick gold triangles with 85-nm side-length, we show that the calculated and experimentally obtained near-field for the excited dipole mode has the same distribution along the polarization of the exciting laser beam. In case of bigger triangles of 540-nm side-length a quadrupole mode is excited, which leads to a rotation of the near-field distribution by 90A degrees referred to the polarization of the beam. This effect is also shown in the FDTD simulations.