Optical nonlinearity enhancement of graded metallic films
Optical nonlinearity enhancement of graded metallic films
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DOI：
10.1063/1.1769086
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发表时间：
2004-05
影响因子：
4
通讯作者：
Jintang Huang;Kin Wah Yu
中科院分区：
文献类型：
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作者：
Jintang Huang;Kin Wah Yu
研究了弱非线性梯度金属薄膜的有效线性极化率和三阶非线性极化率。由于几何结构简单，我们能够精确地推导出具有Drude介电梯度分布的梯度结构内部的局域场。计算了材料的有效线性介电常数和三阶非线性极化率。研究了表面等离子体共振效应对梯度金属薄膜的光学吸收、光学非线性增强和优值系数的影响。研究发现，金属薄膜中灰度的存在在光学区域产生了一个较宽的共振等离子体激元带，导致光学非线性得到较大的增强，从而获得了较大的优值系数。我们建议进行实验来验证我们的理论预测，因为梯度金属薄膜比梯度粒子更容易制备。
The effective linear and third-order nonlinear susceptibility of graded metallic films with weak nonlinearity have been investigated. Due to the simple geometry, we were able to derive exactly the local field inside the graded structures having a Drude dielectric gradation profile. We calculated the effective linear dielectric constant and third-order nonlinear susceptibility. We investigated the surface plasmon resonant effect on the optical absorption, the optical nonlinearity enhancement, and the figure of merit of graded metallic films. It is found that the presence of gradation in metallic films yields a broad resonant plasmon band in the optical region, resulting in a large enhancement of the optical nonlinearity, and hence a large figure of merit. We suggest experiments be done to check our theoretical predictions, because graded metallic films can be fabricated more easily than graded particles.