Combining both localized surface plasmon polaritons (LSPPs) and propagating surface plasmon polaritons, remote surface-enhanced Raman scattering (SERS) emerges as a novel sensing technology in recent years, which could avoid the overlap of incident light and inelastic scattering light in SERS. Compared to traditional SERS, it has novel applications in sensors, plasmon-driven surface-catalyzed reactions, Raman optical activity, etc. However, the weak Raman intensity of remote SERS impedes its further application. In this work, we demonstrated that the remote SERS signals could be enhanced by more than 100% through the subwavelength interference in dual-path-excited Ag-branched nanowire dimer and nanowire–nanoparticle systems. Our experiment has revealed that remote SERS intensities could be modulated by polarization and phase differences of two incident lights illuminating at two separate nanowire terminals. The simulated electromagnetic field distributions through the finite-difference time-domain (FDTD) method indicate that subwavelength interference occurs in Ag nanowires, which causes the Raman intensities collected at a remote site is greatly influenced by the coherent superposition of propagating surface plasmon polaritons (PSPPs). Our work on this coherent enhancement could not only promote the application of remote SERS but also enlarge the research on light manipulating in the subwavelength.

中文翻译：

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双路径激励远程SERS的相干增强。

结合局部表面等离子体激元和传播的表面等离子体激元，远程表面增强拉曼散射（SERS）是近年来出现的一种新型传感技术，它可以避免SERS中入射光和非弹性散射光的重叠。与传统的SERS相比，它在传感器，等离激元驱动的表面催化反应，拉曼光学活性等方面具有新颖的应用。但是，远程SERS的拉曼强度弱阻碍了其进一步的应用。在这项工作中，我们证明了在双路径激发的银支化纳米线二聚体和纳米线-纳米粒子系统中，通过亚波长干扰可以将远程SERS信号增强100％以上。我们的实验表明，可以通过照射在两个单独的纳米线末端的两个入射光的偏振和相位差来调节远程SERS强度。通过时域有限差分法（FDTD）进行的模拟电磁场分布表明，Ag纳米线中发生了亚波长干扰，这导致在远处收集的拉曼强度受到传播表面等离振子极化子（PSPPs）的相干叠加的极大影响。 ）。我们对这种相干增强的研究不仅可以促进远程SERS的应用，而且可以扩大对亚波长光操纵的研究。通过时域有限差分法（FDTD）进行的模拟电磁场分布表明，Ag纳米线中发生了亚波长干扰，这导致在远处收集的拉曼强度受到传播表面等离振子极化子（PSPPs）的相干叠加的极大影响。 ）。我们对这种相干增强的研究不仅可以促进远程SERS的应用，而且可以扩大对亚波长光操纵的研究。通过时域有限差分法（FDTD）进行的模拟电磁场分布表明，Ag纳米线中发生了亚波长干扰，这导致在远处收集的拉曼强度受到传播表面等离振子极化子（PSPPs）的相干叠加的极大影响。 ）。我们对这种相干增强的研究不仅可以促进远程SERS的应用，而且可以扩大对亚波长光操纵的研究。