%0 Journal Article
%T Enhanced optical nonlinear absorption of graded Au--TiO2 composite films<br>
%A Liu Li
%A Su Xiong-Rui
%A <br>
%J 中国物理 B
%D 2008
%I 
%X This paper reports that single-layer and graded Au--TiOAu--TiOAu--TiO$_{2}$ granular composites, graded composite films, $Z$-scan, optical nonlinear absorptionProject supported by the National Natural Science Foundation of China (Grant No 10474075).4270, 7820This 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.
%K Au--TiOAu--TiO$_{2}$ granular composites
%K graded composite films
%K $Z$-scan
%K optical nonlinear absorption<br>
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=47EA7CFDDEBB28E0&jid=CD8D6A6897B9334F09D8D1648C376FB4&aid=06AFBC3AD18C7CDB059FB822BFB388D5&yid=67289AFF6305E306&vid=BCA2697F357F2001&iid=B31275AF3241DB2D&sid=7032F4C1AAED728E&eid=A7C70BFDC1EB80E9&journal_id=1009-1963&journal_name=中国物理&referenced_num=0&reference_num=0