用Z-扫描技术研究卟啉铜偶合TiO2/SiO2有机-无机材料的非线性吸收特性

应用溶胶-凝胶技术, 成功地把5,10,15,20-四(4-磺酸苯基)卟啉铜掺杂到SiO₂/TiO₂无机凝胶中, 制备成有机-无机复合材料. 采用开孔Z-扫描技术, 使用波长532 nm、脉宽7ns的YAG脉冲激光为光源, 测定了不同浓度卟啉铜掺杂的SiO₂/TiO₂凝胶Z-扫描曲线. 应用Z扫描理论对获得的曲线进行分析与理论拟合, 得到复合材料的非线性吸收系数. 这些非线性吸收是由材料中卟啉铜的单聚体与二聚体的反饱和吸收所引起. 研究表明, 随着掺杂浓度的增大, 复合材料的非线性吸收明显增强. 掺杂浓度为1.11×10^-4 (A2), 1.48×10^-4 (A3)与3.01×10^-4 mol/L (A4)凝胶的非线性吸收系数分别为1.705×10^-11, 1.892×10^-11和4.854×10^-11 m/W. 讨论了单聚体与二聚体的浓度变化对非线性吸收的影响. 随着掺杂浓度的增加, 凝胶中二聚体与多聚体含量的增加, 导致非线性吸收系数的增大. 同时测定了无机材料对该光源的抗激光损伤阈值为～5 J/cm².

Nonlinear absorption properties of Cu(II)meso-tetra(4-sulfonatopheny1) porphine in TiO2/SiO2 organic-inorganic gel using Z-scan technique

The Cu（II）meso-tetra（4-sulfonatophenyl） porphines（Cu（II）-TPPS） with various concentrations are incorporated into TiO₂/SiO₂ to form organic and inorganic composite gels via sol-gel process.With a Nd:YAG laser of 532 nm wavelength and 7 ns pulse width, the curves of Z-scan are measured under the condition of open aperture.Nonlinear absorption parameters of these materials,which are attributed to the reverse saturation absorptions of monomer and dimer of Cu（II）-TPPS,are obtained by fitting the above curves with Z-scan theroy.The result indicates that the nonlinear parameter of gel increases with doping concentration increasing.The nonlinear absorption coefficients of gels in 1.11×10^-4 mol/L A2,1.48×10^-4 mol/L A3 and 3.01×10^-4 mol/L A4 doping concentration are 1.705×10^-11,1.892×10^-11,and 4.854×10^-11 m/W,respectively.The effects of monomer and dimer on the nonlinear parameter are discussed.The reduction of the nonlinear parameter results from the increases of dimer and multimer as the doping concentration increases.The damage threshold of the gel is also measured and can reach up to 5 J/cm^-2.