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arXiv 0704.0703physics.optics
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表面等离子体激元在亚波长槽中散射的瞬态行为

Transient behavior of surface plasmon polaritons scattered at a subwavelength groove

Gaetan Leveque, Olivier J. F. Martin, John Weiner

摘要:

我们提出了一个数值研究和分析模型的光学近场衍射在附近的亚波长槽铣银表面。格林张量的方法允许计算的相位和振幅依赖的衍射波作为一个功能的槽的几何形状。结果表明,沿界面衍射的场的槽是等效的替代槽的振荡偶极线源。从格林函数的形式主义,以及再现渐近表面等离子体激元(SPP)波以及瞬态表面波在近区靠近凹槽的解析表达式。该模型与完整模拟之间的一致性非常好,表明瞬态"近区"制度不依赖于凹槽的精确形状。最后,它表明,复合衍射倏逝波模型,包括渐近SPP可以描述在这个瞬态近区的波长演化。这样的半解析模型可能有助于设计和优化更精细的光子电路,其行为在很大程度上将由表面波控制。

英文摘要:

We present a numerical study and analytical model of the optical near-field diffracted in the vicinity of subwavelength grooves milled in silver surfaces. The Green's tensor approach permits computation of the phase and amplitude dependence of the diffracted wave as a function of the groove geometry. It is shown that the field diffracted along the interface by the groove is equivalent to replacing the groove by an oscillating dipolar line source. An analytic expression is derived from the Green's function formalism, that reproduces well the asymptotic surface plasmon polariton (SPP) wave as well as the transient surface wave in the near-zone close to the groove. The agreement between this model and the full simulation is very good, showing that the transient "near-zone" regime does not depend on the precise shape of the groove. Finally, it is shown that a composite diffractive evanescent wave model that includes the asymptotic SPP can describe the wavelength evolution in this transient near-zone. Such a semi-analytical model may be useful for the design and optimization of more elaborate photonic circuits whose behavior in large part will be controlled by surface waves.

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