Nonlinear scattering in gold nanospheres

Po Ting Shen, Cheng Wei Lin, Hsiang Lin Liu, Shi Wei Chu

研究成果: 書貢獻/報告類型會議論文篇章

摘要

Nonlinearity enhanced by noble metallic nanoparticles provide novel light manipulation capabilities and innovative applications. Recently, we discovered a new nonlinear phenomenon on the scattering of metallic nanoparticles by continuous-wave (CW) lasers at the intensity around MW/cm2 and applied to super-resolution microscopy that allowed spatial resolution of plasmonic nanostructures down to λ/8. However, its mechanism is still unknown. In this work, we elaborate the mechanism behind the nonlinear scattering of gold nanospheres. There are four possible candidates: intraband transition, interband transition, hot electron, and hot lattice. Each of them has a corresponding nonlinear refractive index (n2), which is related to temporal dependence of its light-matter interaction. We first measure the intensity dependence of nonlinear scattering to extract the effective n2 value. We find out it has the closest n2 value to hot lattice, which causes either the shift or weakening of the surface plasmon resonance (SPR). To further verify the mechanism, the nanospheres are heated up with both a hot plate and a CW laser, and the variation of single-particle SPR scattering spectra are measured. In both cases, more than 50% reduction of scattering is observed, when temperature rises a few tens of degrees or when illumination intensity reaches the order of 1MW/cm2. Thus, we conclude the spectra variation by the two different heating source, as well as the nonlinear scattering are all due to hot lattice, and subsequent permittivity change with temperature. The innovative concept of hot lattice plasmonics not only opens up a new dimension for nonlinear plasmonics, but also predicts the potential of similar nonlinearity in other materials as long as their permittivity changes with temperature.

原文英語
主出版物標題Physics and Simulation of Optoelectronic Devices XXIV
編輯Yasuhiko Arakawa, Bernd Witzigmann, Marek Osinski
發行者SPIE
ISBN(電子)9781628419771
DOIs
出版狀態已發佈 - 2016 一月 1
事件Physics and Simulation of Optoelectronic Devices XXIV - San Francisco, 美国
持續時間: 2016 二月 152016 二月 18

出版系列

名字Proceedings of SPIE - The International Society for Optical Engineering
9742
ISSN(列印)0277-786X
ISSN(電子)1996-756X

其他

其他Physics and Simulation of Optoelectronic Devices XXIV
國家/地區美国
城市San Francisco
期間2016/02/152016/02/18

ASJC Scopus subject areas

  • 電子、光磁材料
  • 凝聚態物理學
  • 電腦科學應用
  • 應用數學
  • 電氣與電子工程

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