Zhao Jingyi, Cheng Yuqing, Shen Hongming, Hui Yuen Yung, Wen Te, Chang Huan-Cheng, Gong Qihuang, Lu Guowei
State Key Laboratory for Mesoscopic Physics & Collaborative Innovation Center of Quantum Matter, Department of Physics, Peking University, Beijing, 100871, China.
Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 104 Taiwan, China.
Sci Rep. 2018 Feb 26;8(1):3605. doi: 10.1038/s41598-018-22019-z.
In the surface-enhanced fluorescence (SEF) process, it is well known that the plasmonic nanostructure can enhance the light emission of fluorescent emitters. With the help of atomic force microscopy, a hybrid system consisting of a fluorescent nanodiamond and a gold nanoparticle was assembled step-by-step for in situ optical measurements. We demonstrate that fluorescent emitters can also enhance the light emission from gold nanoparticles which is judged through the intrinsic anti-Stokes emission owing to the nanostructures. The light emission intensity, spectral shape, and lifetime of the hybrid system were dependent on the coupling configuration. The interaction between gold nanoparticles and fluorescent emitter was modelled based on the concept of a quantised optical cavity by considering the nanodiamond and the nanoparticle as a two-level energy system and a nanoresonator, respectively. The theoretical calculations reveal that the dielectric antenna effect can enhance the local field felt by the nanoparticle, which contributes more to the light emission enhancement of the nanoparticles rather than the plasmonic coupling effect. The findings reveal that the SEF is a mutually enhancing process. This suggests the hybrid system should be considered as an entity to analyse and optimise surface-enhanced spectroscopy.
在表面增强荧光（SEF）过程中，众所周知，等离子体纳米结构可以增强荧光发射体的光发射。借助原子力显微镜，逐步组装了由荧光纳米金刚石和金纳米颗粒组成的混合系统，用于原位光学测量。我们证明，荧光发射体也可以增强金纳米颗粒的光发射，这是通过由于纳米结构引起的固有反斯托克斯发射来判断的。混合系统的光发射强度、光谱形状和寿命取决于耦合配置。通过将纳米金刚石和纳米颗粒分别视为二能级能量系统和纳米谐振器，基于量子化光学腔的概念对金纳米颗粒与荧光发射体之间的相互作用进行了建模。理论计算表明，介电天线效应可以增强纳米颗粒感受到的局部场，这对纳米颗粒光发射增强的贡献比对等离子体耦合效应的贡献更大。研究结果表明，SEF是一个相互增强的过程。这表明混合系统应被视为一个整体来分析和优化表面增强光谱。
