Excited--state nonlinear optical properties of metal cluster W$_{2}$Ag$_{4}$S$_{8}$(dppf)$_{2}$
金属团簇化合物W2Ag4S8(dppf)2激发态非线性光学性质

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) was deter mined for the cluster. The experiment results show that the cluster W2Ag4S8(dppf)2 has good optical limiting character for nanometer pulse.