中国物理B ›› 2022, Vol. 31 ›› Issue (6): 64208-064208.doi: 10.1088/1674-1056/ac3737

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Ultrafast plasmon dynamics in asymmetric gold nanodimers

Bereket Dalga Dana1, Alemayehu Nana Koya2, Xiaowei Song(宋晓伟)1,†, and Jingquan Lin(林景全)1,‡   

  1. 1 School of Science, Changchun University of Science and Technology, Changchun 130022, China;
    2 Department of Physics, College of Natural and Computational Sciences, Wolaita Sodo University, P. O. Box 138, Wlaita Sodo, Ethiopia
  • 收稿日期:2021-08-20 修回日期:2021-10-27 接受日期:2021-11-06 出版日期:2022-05-17 发布日期:2022-05-26
  • 通讯作者: Xiaowei Song, Jingquan Lin E-mail:songxiaowei@cust.edu.cn;linjingquan@cust.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 91850109 and 61775021), "111" Project of China (Grant No. D17017), Key Laboratory of Ultrafast and Extreme Ultraviolet Optics of Jilin Province, and Ministry of Education Key Laboratory for Cross-Scale Micro and Nano Manufacturing, Changchun University of Science and Technology.

Ultrafast plasmon dynamics in asymmetric gold nanodimers

Bereket Dalga Dana1, Alemayehu Nana Koya2, Xiaowei Song(宋晓伟)1,†, and Jingquan Lin(林景全)1,‡   

  1. 1 School of Science, Changchun University of Science and Technology, Changchun 130022, China;
    2 Department of Physics, College of Natural and Computational Sciences, Wolaita Sodo University, P. O. Box 138, Wlaita Sodo, Ethiopia
  • Received:2021-08-20 Revised:2021-10-27 Accepted:2021-11-06 Online:2022-05-17 Published:2022-05-26
  • Contact: Xiaowei Song, Jingquan Lin E-mail:songxiaowei@cust.edu.cn;linjingquan@cust.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 91850109 and 61775021), "111" Project of China (Grant No. D17017), Key Laboratory of Ultrafast and Extreme Ultraviolet Optics of Jilin Province, and Ministry of Education Key Laboratory for Cross-Scale Micro and Nano Manufacturing, Changchun University of Science and Technology.

摘要: We theoretically investigate the effect of symmetry breaking on the ultrafast plasmon responses of Au nanodisk (ND) dimers by varying the diameter of one of the constituent nanodisks. In the case of a single ultrafast laser pulse, we demonstrate that the ultrafast responses of Au ND homodimer can be significantly modified due to the effect of symmetry breaking. The symmetric dimer shows a single broad spectral peak, whereas the size-asymmetric dimer shows three spectral peaks. The first system displays at most one temporal maximum and no beats in ultrafast temporal, whereas the second system may have three temporal maxima and two beats due to a combination of broken symmetry and the coherent superposition between various plasmon modes induced by the ultra-short laser pulse. Moreover, the shape of temporal dynamics of the size-asymmetric dimer is significantly deformed due to the excitation of local plasmon modes with different wavelength components. Furthermore, the decay time of the amplitude of the local field is longer and oscillates with a high frequency due to the narrower linewidth and red-shifted spectral peaks. We show that the ultrafast plasmon responses of both dimers can be controlled by varying the relative phase and time delays between a pair of two pulses. Our results will open new paths to understanding ultrafast plasmon responses in asymmetric heterodimers with suitable properties for different applications.

关键词: ultrafast plasmon dynamics, coherent control, spectral intensity, temporal maximum

Abstract: We theoretically investigate the effect of symmetry breaking on the ultrafast plasmon responses of Au nanodisk (ND) dimers by varying the diameter of one of the constituent nanodisks. In the case of a single ultrafast laser pulse, we demonstrate that the ultrafast responses of Au ND homodimer can be significantly modified due to the effect of symmetry breaking. The symmetric dimer shows a single broad spectral peak, whereas the size-asymmetric dimer shows three spectral peaks. The first system displays at most one temporal maximum and no beats in ultrafast temporal, whereas the second system may have three temporal maxima and two beats due to a combination of broken symmetry and the coherent superposition between various plasmon modes induced by the ultra-short laser pulse. Moreover, the shape of temporal dynamics of the size-asymmetric dimer is significantly deformed due to the excitation of local plasmon modes with different wavelength components. Furthermore, the decay time of the amplitude of the local field is longer and oscillates with a high frequency due to the narrower linewidth and red-shifted spectral peaks. We show that the ultrafast plasmon responses of both dimers can be controlled by varying the relative phase and time delays between a pair of two pulses. Our results will open new paths to understanding ultrafast plasmon responses in asymmetric heterodimers with suitable properties for different applications.

Key words: ultrafast plasmon dynamics, coherent control, spectral intensity, temporal maximum

中图分类号:  (Dynamics of nonlinear optical systems; optical instabilities, optical chaos and complexity, and optical spatio-temporal dynamics)

  • 42.65.Sf
81.40.Tv (Optical and dielectric properties related to treatment conditions) 78.47.J- (Ultrafast spectroscopy (<1 psec)) 78.70.-g (Interactions of particles and radiation with matter)