A reduction in the number of loss decay channels present in optical nanoantennas could help enhance an emitter’s radiation efficiency. These losses get amplified for emitters in close proximity to metallic surfaces, such as for self-assembled monolayers, reducing the fluorescence rate. However, such a proximity strongly enhances Raman scattering. A dual-sensing scheme should bypass this shortcoming, and switching from metals to high refractive index dielectrics could aid in that direction. In order to show this, we fabricated silicon nanodimers and coated them with a β-carotenal monolayer for detecting surface-enhanced Raman scattering and fluorescence emission of the same probe. We obtained a surface-enhanced Raman scattering (SERS) factor of 1720 ± 300 for the C–C bond stretching of the polyene chain and a surface fluorescence enhancement (SEF) factor of 470 ± 90. Furthermore, our theoretical studies of different materials and emitters located on the surface of nanostructures demonstrate that low-loss dielectric materials provide a robust architecture for enhancing the response of efficient emitters. These results could have a direct impact on the development of deterministic high-rate single-photon sources.

中文翻译：

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全介电纳米天线中分子单层的表面增强光谱。

光学纳米天线中损耗衰减通道数量的减少可以帮助提高发射器的辐射效率。对于靠近金属表面的发射器（例如自组装单层膜），这些损耗会被放大，从而降低荧光率。但是，这样的接近性极大地增强了拉曼散射。双感测方案应该绕过这个缺点，从金属切换到高折射率电介质可以在这个方向上有所帮助。为了证明这一点，我们制造了硅纳米二聚体，并用β-胡萝卜素单层涂覆它们，以检测同一探针的表面增强拉曼散射和荧光发射。对于多烯链的C–C键拉伸，我们获得的表面增强拉曼散射（SERS）因子为1720±300，表面荧光增强（SEF）因子为470±90。位于纳米结构表面的发射极表明，低损耗介电材料提供了一种坚固的体系结构，可增强有效发射极的响应。这些结果可能直接影响确定性高速率单光子源的发展。