We report on the experimental observation of mirror-enhanced directional surface-enhanced Raman scattering (SERS) from a self-assembled monolayer of molecules coupled to a nanowire-nanoparticle (NW-NP) junction on a mirror in a remote excitation configuration. Placing the NW-NP junction on a metallic mirror generates multiple gap plasmon modes that have unique momentum space-scattering signatures. We perform Fourier plane imaging of the SERS from the NW-NP on a mirror to understand the effect of multiple hotspots on molecular emission. We systematically study the effect of the ground plane on the directionality of emission from the NW-NP junction and show that the presence of a mirror drastically reduces the angular spread of emission. The effect of multiple hotspots in the geometry on the directionality of the molecular emission is studied using 3D numerical simulations. The results presented here will have implications in understanding plasmon hybridization in the momentum space and its effects on molecular emission.

我们报告了镜面增强定向表面增强拉曼散射 (SERS) 的实验观察结果，该实验观察到在远程激发配置的镜子上耦合到纳米线-纳米粒子 (NW-NP) 结的自组装分子单层。将 NW-NP 结放在金属镜上会产生多个间隙等离子体模式，这些模式具有独特的动量空间散射特征。我们在镜子上对来自 NW-NP 的 SERS 进行傅立叶平面成像，以了解多个热点对分子发射的影响。我们系统地研究了地平面对 NW-NP 结发射方向性的影响，并表明镜子的存在大大减少了发射的角展。使用 3D 数值模拟研究几何中的多个热点对分子发射方向性的影响。这里介绍的结果将对理解动量空间中的等离子体杂交及其对分子发射的影响产生影响。