Ultrafast electron dynamics and enhanced optical nonlinearities of CdS-capped Au∕BaTiO3 composite film
Ultrafast electron dynamics and enhanced optical nonlinearities of CdS-capped Au∕BaTiO3 composite film
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DOI：
10.1063/1.2001727
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发表时间：
2005-08
影响因子：
3.2
通讯作者：
Yong Yang;M. Nogami;Jianlin Shi;Hangrong Chen;Ye Liu;S. Qian
中科院分区：
文献类型：
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作者：
Yong Yang;M. Nogami;Jianlin Shi;Hangrong Chen;Ye Liu;S. Qian
利用800 nm非共振飞秒光学克尔效应技术，研究了不同厚度的硫化镉包覆在钛酸钡薄膜中的金纳米粒子的三阶非线性光学响应。金-硫化镉核-壳复合纳米粒子的非线性比其单一组分有明显的增强，χ(3)值随着硫化镉壳层厚度的增加而明显增大。复合纳米粒子中的电场分布是用Neve的理论计算的[A.E.Neeves和M.H.Birnboim，J.Opt。SoC。上午好。B6,787(1989)]，解释了非线性增强机制，这主要归因于硫化镉壳层中局域电场的增强。利用800 nm处的时间分辨泵浦-探测技术，发现具有核壳结构的Au-CDS纳米粒子中的电子弛豫动力学与纯金纳米粒子系统中的相同。
The third-order nonlinear optical responses of gold nanoparticles capped by CdS shells of different thicknesses embedded in BaTiO3 films were investigated by off-resonance femtosecond optical Kerr effect technology at 800nm. The nonlinearities of the Au–CdS core-shell composite nanoparticles exhibit a significant enhancement, compared with their single components, and the χ(3) value apparently increases with the increase in the CdS shell thickness. The electric-field distribution in the composite nanoparticles was calculated using Neeve’s theory [A. E. Neeves and M. H. Birnboim, J. Opt. Soc. Am. B 6, 787 (1989)] to explain the nonlinear enhancement mechanism, which was mainly attributed to the enhancement of the localized electric field in the CdS shell. The electron relaxation dynamics in the Au–CdS nanoparticles with a core-shell structure were found to be the same as that in pure gold nanoparticle systems using the time-resolved pump-probe technique measured at 800nm.