Ag:Bi_2O_3复合膜的线性和非线性光学性质

Linear and nonlinear optical properties of Ag:Bi_2O_3 composite films

从实验和理论两个方面,探讨了金属Ag不同掺杂浓度对Ag:Bi2O3复合膜线性和非线性光学性质的影响.用吸收光谱研究了Ag浓度与Ag:Bi2O3复合膜表面等离子体共振带之间的关系;用皮秒Z-扫描技术研究了共振和非共振情况下(激发光波长分别为532nm和1064nm),金属Ag浓度与复合膜三阶非线性极化率的关系.基于表面等离子体共振理论和局域场增强理论对复合膜进行了分析,得到了不同Ag浓度时Ag:Bi2O3复合膜的三阶非线性效应,研究了激发波长和金属浓度对复合膜线性和非线性光学性质的影响.结果表明,等离子体共振增强和合适的金属掺杂浓度使得三阶极化率增强二个量级,在Ag浓度为35%左右和接近等离子体共振频率(相应吸收带位于560nm—622nm)的532nm激发时,χ(3)具有最大值2.4×10-9esu.

On the basis of measurements and theoretical analysis, linear and nonlinear optical properties on the Ag ： Bi2 O3 composite films with different Ag concentrations were investigated. The relationship between the Ag concentrations and the surface plasmon resonance （SPR） of Ag： Bi2O3 composite films were characterized by UV-VIS-NIR spectroscopy, and the dependence of third- order nonlinear susceptibility of composite films on Ag concentrations was investigated by picosecond Z-scan technique with different excitation wavelength （532 nm and 1064 nm）. The analysis of optical properties of these films was carried out using the theories of surface plasmon resonance and localized field enhancement respectively. From the experimental and theoretical results, the dependence of third-order nonlinear susceptibilities χ^（3） on Ag concentration was shown. With Ag concentration around 35 % and the excitation wavelength at 532 nm near the surface plasmon resonance （560 nm--622 nm）, the third-order nonlinear susceptibility χ ^（3） showed a maximum value of 2.4×10^-9 esu.