中国物理B ›› 2008, Vol. 17 ›› Issue (6): 2170-2174.doi: 10.1088/1674-1056/17/6/038

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Enhanced optical nonlinear absorption of graded Au--TiO2 composite films

刘莉1, 苏雄睿2   

  1. (1)College of Electronics & Information Engineering, Wuhan University of Science and Engineering, Wuhan 430073, China;Department of Physics, Wuhan University, Wuhan 430072, China; (2)Department of Physics, Wuhan University, Wuhan 430072, China
  • 收稿日期:2007-10-22 修回日期:2007-11-16 出版日期:2008-06-20 发布日期:2008-06-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10474075).

Enhanced optical nonlinear absorption of graded Au--TiO2 composite films

Liu Li(刘莉)a)b)† and Su Xiong-Rui(苏雄睿)b)   

  1. a College of Electronics & Information Engineering, Wuhan University of Science and Engineering, Wuhan 430073, China; b Department of Physics, Wuhan University, Wuhan 430072, China
  • Received:2007-10-22 Revised:2007-11-16 Online:2008-06-20 Published:2008-06-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10474075).

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摘要： This paper reports that single-layer and graded Au--TiO$_{2}$ granular composite films with Au atom content 15{\%}--66{\%} were prepared by using reactive co-sputtering technique. The third-order optical nonlinearity of single-layer and graded composite films was investigated by using s- and p-polarized $Z$-scans in femtosecond time scale. The nonlinear absorption coefficient \textit{$\beta $}$_{\rm eff}$ of single-layer Au--TiO$_{2}$ films is measured to be --2.3$\times $10$^{3}-$0.76$\times $10$^{3}$ cm/GW with Au atom content 15{\%}--66{\%}. The \textit{$\beta $}$_{\rm eff}$ value of the 10-layer Au--TiO$_{2}$ graded film is enhanced to be --2.1$\times $10$^{4}$cm/GW calculated from p-polarized $Z$-scans, which is about ten times the maximum \textit{$\beta $}$_{\rm eff}$ of single-layer films. Broadened response in the wavelength region 730--860\,nm of the enhanced optical nonlinearity of graded Au--TiO$_{2}$ composite films was also investigated.

关键词: Au--TiO$_{2}$ granular composites, graded composite films, $Z$-scan, optical nonlinear absorption

Abstract: This paper reports that single-layer and graded Au--TiO$_{2}$ granular composite films with Au atom content 15%--66% were prepared by using reactive co-sputtering technique. The third-order optical nonlinearity of single-layer and graded composite films was investigated by using s- and p-polarized $Z$-scans in femtosecond time scale. The nonlinear absorption coefficient $\beta_{\rm eff}$ of single-layer Au--TiO$_{2}$ films is measured to be --2.3$\times $10$^{3}-$0.76$\times $10$^{3}$ cm/GW with Au atom content 15%--66%. The $\beta_{\rm eff}$ value of the 10-layer Au--TiO$_{2}$ graded film is enhanced to be --2.1$\times $10$^{4}$cm/GW calculated from p-polarized $Z$-scans, which is about ten times the maximum $\beta _{\rm eff}$ of single-layer films. Broadened response in the wavelength region 730--860 nm of the enhanced optical nonlinearity of graded Au--TiO$_{2}$ composite films was also investigated.

Key words: Au--TiO$_{2}$ granular composites, graded composite films, $Z$-scan, optical nonlinear absorption

中图分类号:  (Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity))

  • 78.20.Ci
42.65.An (Optical susceptibility, hyperpolarizability) 42.65.Re (Ultrafast processes; optical pulse generation and pulse compression) 78.66.-w (Optical properties of specific thin films)