金薄膜衬底上介质-金属核壳结构的光学力调控

Jia chen Zhang, Wei xing Yu, Fa jun Xiao, Jian lin Zhao

科研成果: 期刊稿件文章同行评审

1 引用 (Scopus)

摘要

Manipulating the core-shell structure with the optical force has been extensively studied, giving birth to applications such as particle sorting, biomarkers and drug delivery. Tailoring the optical force exerted on the core-shell above the metallic film remains unexplored, despite the obvious benefits for both fundamental research and applications including strong coupling, surface enhanced spectroscopy, nanolaser, and nanoscale sensing. In this work, we systematically investigate the optical force exerted on a dielectric/metal core-shell above a gold film by utilizing the Maxwell stress tensor formalism. It is found that at the present gold substrate, the optical force on the core-shell can be one order of magnitude larger than that on the individual core-shell due to the strong coupling between the core-shell and the gold film. Interestingly, the direction of the optical force can be reversed from positive to negative by distributing the local field from the upside of core-shell to the structure gap through changing the excitation wavelength. Furthermore, we demonstrate that the magnitude and peak wavelength of the optical force can be well controlled by altering the structure gap, the size and refractive index of the core. More specifically, it is found that the coupling strength between the core-shell and the gold film decreases with the gap size increasing. As a result, we observe the blue shift of bonding mode and the decrease of local field in the gap, which leads the force peak wavelength to be blue-shifted and the force peak magnitude to decrease, respectively. Also, by increasing the radius and refractive index of the core, a red shift of force peak is accompanied with the red shift of the bonding mode. In addition, the force peak magnitude follows the same trend as the total local field enhancement factor when the radius and refractive index of the core change. We hope that our results open the way to control the cavity size of particle on film structure, which would be beneficial for tailoring the light matter interaction even down to single molecular level and promises to have the applications in novel functional photonic devices.

投稿的翻译标题Tuning optical force of dielectric/metal core-shell placed above Au film
源语言繁体中文
文章编号184206
期刊Wuli Xuebao/Acta Physica Sinica
69
18
DOI
出版状态已出版 - 20 9月 2020
已对外发布

关键词

  • Core-shell structure
  • Optical force
  • Plasmon hybridization
  • Surface plasmons

指纹

探究 '金薄膜衬底上介质-金属核壳结构的光学力调控' 的科研主题。它们共同构成独一无二的指纹。

引用此