Metal Cluster Compounds The W <sub> 2 </ Sub> Of Ag <sub> 4 </ Sub> S <sub> 8 </ Sub> (pph <sub> 3 </ Sub>) <sub> 4 </ Sub > And The Mo <sub> 2 </ Sub> Of Ag <sub> 4 </ Sub&g

This dissertation summarized basic theory of nonlinear optics, finds and applications of the optical nonlinear effects, properties of laser weapon, principles of laser protection, characteristic of laser protection materials and parameters of optical limiting.The materials of optical limiting such as semi-conductor, organic macromolecule, fullerene and its ramification, metal cluster and nano-materials were presented respectively. The mechanisms such as self-focusing (self-defocusing), reverse saturation absorption, two-photo absorption, free carrier electron and nonlinear scatting were introduced too. The shapes, sorts, characteristics and applications of metal clusters were recommended. Nonlinear theory and theory of excited-state were also introduced. The steady model under the pico-second (ps) and nano-second (ns) were analyzed. The development, basic theory and correlative academic analysis of a single beam laser Z-scan technique were presented in detail.The research achievements and methods in the recent year of optical nonlinear characteristic and optical limiting property about hexagonal prism shaped metal cluster compounds were reviewed systemically. The materials and principles of optical limiting were summarized too. Comparing with those results, hexagonal prism shaped metal cluster compounds have strong nonlinear property and low linear absorption in vision band in the optical limiting materials of metal cluster. This states that the optical limiting power of hexagonal prism shaped metal cluster maybe strong, so it has a tremendous potential application.The properties of optical nonlinear refraction and absorption for two hexagonal prism shaped metal cluster compounds W2Ag4S8(PPh3)4 and Mo2Ag4S8(PPh3)4 in N,N- dimethyllformaide(DMF) were contrastively investigated using a single beam Z-scan technique. Their strong nonlinear absorption and self-focusing performances were found under nano-second and pico-second laser pulses. Their third-order nonlinear refraction indexes and nonlinear absorption coefficients were calculated. The nonlinear characteristics of former are better than latter which induced by the effect of weight atoms of metal clusters.In this dissertation, the optical limiting properties of the two kinds of metal clusters in DMF with the wavelength of 532 nm, pulse duration of 8 ns and 30 ps, repetition frequency of 1 Hz laser pulses were studied. The experiment results indicate that the optical limiting effect of hexagonal prism shaped metal cluster compound with central atom W is better than that of Mo. The optical limiting mechanisms of two hexagonal prism shaped metal cluster compounds were also analyzed.Study on the nonlinear properties of metal cluster materials redounds to understand physical properties of metal clusters, enriches the theory of optical limiting for metal cluster and can provide experimental foundation for making optical limiting devices.