【摘要】 采用脉冲激光沉积技术在熔石英基片上制备了c轴取向的锐钛矿相TiO2薄膜.通过X射线衍射和原子力显微镜对薄膜的结构、结晶性和表面特性进行了表征.通过透射光谱计算得到TiO2薄膜折射率约为2.1,光学带隙约为3.18eV.结合飞秒激光和Z扫描方法测量了薄膜的超快非线性光学特性,结果表明:锐钛矿TiO2薄膜具有负的非线性吸收系数和负的非线性折射率,其大小分别为-6.2×10-11m/W和-6.32×10-17m2/W,对应的三阶非线性极化率的实部和虚部分别为-7.1×10-11esu和-4.42×10-12esu.并计算薄膜的优值比T=βλ/n2≈0.8,表明锐钛矿相的TiO2在非线性光学器件方面具有潜在的应用前景.更多还原

【Abstract】 Anatase TiO2 films were fabricated on fused quartz by pulsed laser deposition(PLD) technique and the single-phase anatase films were obtained under the optimal conditions.The X-ray diffraction and atomic force microscope were used to investigate the structure and surface characters of the film.The third-order optical nonlinearities of the films were measured by Z-scan technique using a femtosecond laser(50fs) of 800nm.From the transmission spectra,the optical band-gap and linear refractive index of the TiO2 film are determined to be 3.18eV and 2.1,respectively.The nonlinear Absorption coefficient and nonlinear refractive index are determined to be-6.2×10-11m/W and-6.32×10-17m2/W,respectively.The real and imaginary parts of third-order nonlinear susceptibility χ(3) are determined to be-7.1×10-11esu and-4.42×10-12esu,respectively.And the following figure of merit T=βλ/n2 is calculated to be 0.8 for the film,indicating that the anatase TiO2 films have great potential applications to nonlinear optical devices.更多还原