Optical second-harmonic generation of metal-island films
Optical second-harmonic generation of metal-island films
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金属岛薄膜的光学二次谐波产生
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
H. Gold
中科院分区：
文献类型：
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作者：
F. Aussenegg;A. Leitner;H. Gold
在由透明衬底上的纳米粒子组成的金属岛膜中，电子-等离子体共振可以局部增强辐照光场。因此，非线性光学过程需要得到极大的加强。然而，由于金属粒子的中心对称形状，在表面产生二次谐波的二阶非线性过程被强烈地减弱。研究发现，这种表面特性对二次谐波产生的贡献并不像场增强所预期的那样被增强。在光滑的金属表面上的“整体”贡献比来自“真实表面”的贡献要弱得多，没有对称性限制的等离子体共振强烈地增强了这一贡献，并且变得相当重要。
In metal-island films consisting of nanometer particles on a transparent substrate irradiated light fields can be locally enhanced by electron-plasma resonances. Therefore, nonlinear optical processes should be enhanced dramatically. However, second-order nonlinear processes as second-harmonic generation occuring in the surface are strongly reduced by the centrosymmetric shape of the metal particles. It is found that this surface-specific contribution to second-harmonic generation is less enhanced, as is expected from the field enhancement. The “bulk” contribution, at smooth metal surfaces known to be much weaker than the contribution from the “real surface”, is strongly enhanced by the plasma resonances without symmetry restrictions and becomes comparably important.