An extinction theorem for electromagnetic waves in a point dipole model
An extinction theorem for electromagnetic waves in a point dipole model
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点偶极子模型中电磁波的消光定理
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
D. Berman
中科院分区：
文献类型：
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作者：
D. Berman
利用传输矩阵方法表明，电磁波在点偶极立方晶格中传播时，其波速从真空中的c减小到c/n，其中n是折射率，而在空隙中，波速为c。因为晶格不是连续的，所以在晶格平面之间存在倏逝波。这些波最终导致了n的洛伦兹-洛伦兹结果，并在前几个晶格平面中产生偏振的快速变化。这些快速变化表明，存在一个消光长度，在该消光长度上，外部波被转换为以降低的速度传播的内部波。此长度是局部字段采用其批量值的距离。在最近关于埃瓦尔德-奥森定理的工作中，由于只考虑了连续模型，因此忽略了消光长度的可能性。
A transfer matrix method is used to show that an electromagnetic wave in a cubic lattice of point dipoles propagates as if its wave speed has been reduced from c in vacuo to c/n, where n is the index of refraction, while in the interstices the wave speed is c. Because the lattice is not a continuum, there are evanescent waves between lattice planes. These waves ultimately give rise to the Lorentz–Lorenz result for n and produce rapid variations of the polarization in the first few lattice planes. These rapid variations indicate that there is an extinction length over which the external wave is converted to the internal wave propagating at the reduced speed. This length is the distance over which the local field assumes its bulk value. The possibility of an extinction length in recent work on the Ewald–Oseen theorem was missed because only continuum models were considered.