Zhu Shuangmei, Fan Chunzhen, Liang Erjun, Ding Pei, Dong Xiguang, Hao Haoshan, Hou Hongwei, Wu Yuanda
Henan Key Laboratory of Electronic Ceramic Materials and Application and College of Science, Henan University of Engineering, Zhengzhou, 451191, China.
College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China.
Sci Rep. 2021 Jan 13;11(1):1230. doi: 10.1038/s41598-020-78814-0.
A new tactic that using Ag nanorice trimer as surface-enhanced hyper Raman scattering substrate is proposed for realizing maximum signal enhancement. In this paper, we numerically simulate and theoretically analyze the optical properties of the nanorice trimer consisting of two short nanorices and a long nanorice. The Ag nanorice trimer can excite Fano resonance at optical frequencies based on the strong interaction between the bright and the dark mode. The bright mode is attributed to the first longitudinal resonance of the short nanorice pair, while the dark mode originates from the third longitudinal mode resonance of the long nanorice. The electric field distributions demonstrate that the two resonances with the largest field strength correspond to the first-order resonance of the long nanorice and the Fano resonance of the trimer, respectively. Two plasmon resonances with maximum electromagnetic field enhancements and same spatial hot spot regions can match spectrally with the pump and second-order Stokes beams of hyper Raman scattering, respectively, through reasonable design of the trimer structure parameters. The estimated enhancement factor of surface-enhanced hyper Raman scattering can achieve as high as 5.32 × 10.
提出了一种使用银纳米米三聚体作为表面增强超拉曼散射基底的新策略，以实现最大信号增强。本文对由两个短纳米米和一个长纳米米组成的纳米米三聚体的光学性质进行了数值模拟和理论分析。基于亮模式和暗模式之间的强相互作用，银纳米米三聚体可以在光频率下激发法诺共振。亮模式归因于短纳米米对的第一个纵向共振，而暗模式源于长纳米米的第三个纵向模式共振。电场分布表明，场强最大的两个共振分别对应于长纳米米的一阶共振和三聚体的法诺共振。通过合理设计三聚体结构参数，两个具有最大电磁场增强和相同空间热点区域的等离子体共振可以分别在光谱上与超拉曼散射的泵浦光束和二阶斯托克斯光束匹配。表面增强超拉曼散射的估计增强因子可高达5.32×10。
