金属团簇化合物W_2Ag_4S_8(dppf)_2激发态非线性光学性质

Excited-state nonlinear optical properties of metal cluster W_2Ag_4S_8(dppf)_2

用Z扫描方法测量了金属团簇化合物W2Ag4S8(dppf)2的非线性光学响应,发现团簇W2Ag4S8(dppf)2具有显著的反饱和吸收和自聚焦等非线性光学性质.应用激发态理论分析了团簇W2Ag4S8(dppf)2的非线性吸收和非线性折射,结果与实验数据一致.通过数值模拟获得激发态和基态吸收截面比值Ka及非线性折射度比值Kr,阐述了Ka和Kr的物理意义.确定了团簇W2Ag4S8(dppf)2的三阶极化率X(3).团簇化合物W2Ag4S8(dppf)2对脉宽为纳秒的激发脉冲限幅效果比较好.

The nonlinear optical effect of metal cluster compound W2Ag4S8(dppf)2 was investigated using frequency-doubled, Q-switched Nd-YAG pulse laser system with wavelength of 532 nm and pulse width of 8 ns. The cluster W2Ag4S8(dppf)2 possessed reverse saturation absorption and self-focusing refraction. The nonlinear absorption and nonlinear refraction of the cluster W2Ag4S8(dppf)2 were explained with excited-state theory. The theoretical results are in agreement with the experimental data. The ratio of cross-section of the absorption of the excited-state to that of the ground-state Ka and the ratio of refraction volumes of the excited-state to that of the ground-state Kr were gained based on their simulation of numerical value. The effective third-order susceptibility x(3) determined for the cluster. The experiment results show that the cluster W2Ag4S8(dppf)2 has good optical limiting character for nanometer pulse.