We investigate resonance energy transfer (RET) between a donor–acceptor pair above a gold surface (including bulk and thin-film systems) and explore the distance/frequency dependence of RET enhancements using the theory we developed previously. The mechanism of RET above a gold surface can be attributed to the effects of mirror dipoles, surface plasmon polaritons (SPPs), and retardation. To clarify these effects on RET, we analyze the enhancements of RET by the mirror method, the decomposition of s- and p-polarization, and the SPP dispersion of charge-symmetric and charge-antisymmetric modes. We find a characteristic distance (approximately 1/10 of the wavelength) that can be used to classify the dominant effect on RET. Moreover, the characteristic distance can be shortened by narrowing the thickness of the thin-film systems, indicating that SPPs can enhance the rate of RET at a short range. The charge-symmetric and charge-antisymmetric modes of the thin films also allow us to engineer the maximum RET enhancement. We hope that our analysis inspires further investigation into the mechanism of RET coupled with SPPs and its applications.

中文翻译：

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共振能量转移与表面等离激元极化子耦合的特征距离

我们研究了金表面（包括块体和薄膜系统）上方供体-受体对之间的共振能量转移（RET），并使用我们先前开发的理论探索了RET增强的距离/频率依赖性。金表面上方的RET的机理可归因于反射镜偶极子，表面等离激元极化子（SPPs）和延迟。为了阐明这些对RET的影响，我们分析了镜像方法对RET的增强作用，s极化和p极化的分解以及电荷对称和电荷非对称模式的SPP色散。我们发现一个特征距离（大约是波长的1/10），可以用来对RET的主要影响进行分类。此外，可以通过缩小薄膜系统的厚度来缩短特征距离，表明SPP可以在短距离内提高RET的速率。薄膜的电荷对称和电荷非对称模式也使我们能够设计出最大的RET增强。我们希望我们的分析能够激发对RET与SPP结合的机理及其应用的进一步研究。