Surface plasmon polariton propagation near an index step
Surface plasmon polariton propagation near an index step
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DOI：
10.1016/j.optcom.2005.01.014
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发表时间：
2005-05-01
影响因子：
2.4
通讯作者：
Zierau, W
中科院分区：
文献类型：
--
作者：
Leskova, TA;Maradudin, AA;Zierau, W
本文从理论上研究了频率为ω的p偏振光在由介电常数在x（3）> D范围内为ε（0）的电介质（棱镜）、在0 < x（3）< D范围内为复频率依赖的介电函数ε（1）（ω）的金属薄膜、在x（3）> D范围内为ε（1）（ω）的电介质（棱镜）和在x（3）< D范围内为ε（1）（ω）的金属薄膜组成的系统中的散射和透射。介电膜，其特征在于，在xi（x（1））< x（3）< 0的区域中，介电常数为ε（2），在x（3）< xi（x（1））的区域中，为真空（ε（3）= 1）。入射平面为x（1）x（3）平面的光通过棱镜入射。对于表面轮廓函数xi（x（1）），我们假设形式xi（x（1））= -d θ（x（1））θ（L-x（1）），其中θ（x（1））是海维赛德单位阶跃函数。因此，我们具有厚度为d且介电常数为λ（2）的介电膜，其覆盖由0 < x（1）< L定义的金属膜的下表面（x（3）= 0）的部分。导出了散射回棱镜的光的振幅R（q垂直条k）的简化瑞利方程，以及透射到真空中的光的振幅T（q垂直条k）的简化瑞利方程。数值求解这些积分方程，并将结果用于计算散射场的强度在近场和远场区域，和透射光的强度在近场区域，几个值的L和入射光的波长。结果提供了关于在金属-真空界面处由入射光激发的表面等离子体激元的散射的信息，通过该界面上的折射率阶跃，其可用于确定介电膜的厚度d、其范围L和其介电常数ε（2）。(c)2005 Elsevier B. V.保留所有权利。
In this work, we study theoretically the scattering of p-polarized light of frequency omega from, and its transmission through, a system consisting of a dielectric medium (prism) characterized by a dielectric constant epsilon(0) in the region x(3) > D; a metal film characterized by a complex, frequency-dependent dielectric function epsilon(1)(omega) in the region 0 < x(3) < D; a dielectric film characterized by a dielectric constant epsilon(2) in the region xi(x(1)) < x(3) < 0; and vacuum (epsilon(3) = 1) in the region x(3) < xi(x(1)). The light, whose plane of incidence is the x(1)x(3)-plane, is incident through the prism. For the surface profile function xi(x(1)) we assume the form xi(x(1)) = -d theta(x(1))theta(L - x(1)), where theta(x(1)) is the Heaviside unit step function. Thus, we have a dielectric film of thickness d and dielectric constant epsilon(2) covering the part of the lower surface (x(3) = 0) of the metal film defined by 0 < x(1) < L. The reduced Rayleigh equation for the amplitude of the light scattered back into the prism, R(q vertical bar k), is derived, as is the reduced Rayleigh equation for the amplitude of the light transmitted into the vacuum, T(q vertical bar k). These integral equations are solved numerically and the results are used to calculate the intensity of the scattered field in the near- and far-field regions, and the intensity of the transmitted light in the near-field region, for several values of L and of the wavelength of the incident light. The results provide information about the scattering of the surface plasmon polariton at the metal-vacuum interface, excited by the incident light, by index steps on that interface, which can be used to determine the thickness of the dielectric film d, its extent L, and its dielectric constant epsilon(2). (c) 2005 Elsevier B.V. All rights reserved.