1. A Sign Alternation of Nonlinear Absorption in Gold Composite Films in Z-Scan
- Author
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Xiao Si, Han Jun-Bo, Wang Qu-Quan, Ding Sha, Zhou Hui-Jun, Chen Dai-Jian, and Xiong Gui-guang
- Subjects
Optical nonlinearity ,Nonlinear absorption ,Materials science ,Reverse saturable absorption ,Femtosecond ,Composite number ,Analytical chemistry ,Alternation (geometry) ,General Physics and Astronomy ,Z-scan technique ,Atomic physics ,Saturation (magnetic) - Abstract
Au–TiO2 composite films with Au atom content varying from about 15% to 82% are prepared by co-sputtering technique. Both open- and closed-aperture Z-scan of the samples are performed in the femtosecond time region. A conversion of the nonlinear absorption from negative to positive is observed as the Au atom content increases due to the saturation of reverse saturable absorption. The nonlinear refractive index γ and effective nonlinear absorption coefficient βeff at the Au atom content of 54% are measured to be 1.6×10−2 cm2/GW and −2.6×103 cm/GW, respectively. The corresponding third-order optical nonlinearity χ(3) is about 6.3×10−8 esu.
- Published
- 2005
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