A Sign Alternation of Nonlinear Absorption in Gold Composite Films in Z-Scan
-
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 1.6×10-2cm2/GW and -2.6×103cm/GW, respectively. The corresponding third-order optical nonlinearity x(3) is about 6.3×10-8esu.
Article Text
-
-
-
About This Article