Te/TeO_2-SiO_2复合薄膜的吸收和非线性光学特性研究

Absorption and nonlinear optical properties of Te/TeO_2-SiO_2 composite films

应用分光光度计测量Te/TeO2-SiO2复合薄膜的透射光谱和吸收光谱,在480nm附近观察到Te颗粒引起的等离子体共振吸收峰;采用Z扫描技术研究了共振(激发波长为532nm)和非共振情况下(激发波长1064nm)不同电位制备薄膜的Te颗粒状态与复合薄膜的三阶非线性极化率的关系.基于有效介质理论对复合薄膜的三阶非线性效应进行分析,研究Te颗粒大小对Te/TeO2-SiO2复合薄膜的非线性光学性质的影响及其产生机理.结果表明薄膜制备过电位增大,Te的粒径减小,颗粒数量多,颗粒分布趋于均匀,使得金属颗粒的表面等离子体共振峰红移,吸收强度增强,导致三阶非线性光学效应增强,χ(3)由1064nm的5.12×10-7esu增大为532nm的8.11×10-7esu.

The transmission and absorption spectra of the Te/TeO2-SiO2 thin film were obtained by using a spectrophotometer, with the surface plasmon rensoance （SPR） observed at 480 nm. While the dependence of the third-order nonlinear susceptibility of composite films on the Te particle was investigated by Z-scan technique with renosant wavelength （532 nm） and non-renosant wavelength （1064 nm）. Optical properties of these films was analyzed using the effective medium theory, and the relationship was investigated to obtain Te particle size and nonlinear optical properties of Te/TeO2-SiO2 films. The results show that the Te particle size was smaller, the number of particles was increased, and the particle distribution tends to be uniform. The surface plasmon resonance peak was red-shifted, and the absorption intensity was enhanced; and the third-order nonlinear optical effects was enhanced, χ（3） was increased by 5.12×10-7 esu at 1064 nm to 8.11×10-7 esu at 532 nm with preparation potential increased.