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主要从实验和理论两个方面,探讨了不同Au颗粒尺寸和不同基质对Au:TiO2和Au:Al2O3复合膜线性和非线性光学性质的影响.用吸收光谱研究了Au颗粒尺寸和基质与Au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),Au颗粒尺寸和基质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Au颗粒大小和不同基质时Au复合膜的三阶非线性效应,研究了金属尺寸和基质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大的金属颗粒以及等离子体共振增强和大介电常数的基质均使得三阶极化率增强近二个量级,且其中颗粒增强占主导地位,在Au颗粒大小为35nm、介电常数较大的TiO2为基质和接近等离子体共振频率(相应吸收带位于618—632nm)的532nm激发时,χ(3)具有最大值2.5×10-9esu.
The effects of different Au particle size and different matrix on the linear and nonlinear optical properties of Au: TiO2 and Au: Al2O3 composite films were discussed from two aspects of experiment and theory, and the relationship between Au particle size and Au / The relationship between the plasmon resonance bands and the surface plasmon resonance bands was investigated by the picosecond Z-scan technique. The effects of resonance and nonresonance (excitation wavelength of 532 nm and 1064 nm, respectively), Au particle size and the third-order nonlinear polarization The relationship between the size and matrix of Au composite films was investigated based on the surface plasmon resonance theory and the local field enhancement theory. The third-order nonlinearity of the Au composite films with different Au particle sizes and different matrixes was obtained. Linear and nonlinear optical properties of the composite films.The results show that the third order polarizability is enhanced by nearly two orders of magnitude due to the enhancement of the plasmon resonance and the large size of the metal particles and the enhancement of the plasmon resonance and the large dielectric constant Among them, particle enhancement dominates in the Au particle size of 35nm, the larger the dielectric constant of TiO2 as the matrix and near the plasma resonance frequency (corresponding absorption band at 618-632n m), χ (3) has a maximum of 2.5x10-9 esu.