Nonlinear Optical Properties And Optical Limiting Properties Study Of Nickel Complexes

Nickel and its metal complexes not only have great importance to study ofchemical science, but also have comprehensive applications to the field of technique. Meanwhile, the extensive interest of spectroscopists and academic chemists has been arosed by high symmetry and particular electronic structure of nickel one- nuclear complexes. So, in our thesis, the nonlinear optical properties and passive optical limiting properties of nickel one- nuclear complexes have been investigated.Mansoor Sheik Bahae introduced a high sensitive single-beam Z-scan technique inl989. It requires relatively simple experimental apparatus and simple analysis. Z-scan technique has been widely employed since it was reported. Now, it has become an important method in studying the nonlinear optical characteristics.Nonlinear optics have been widely applied and profusely researched, in our article, its main phenomena and effects have been briefly summarized. The investigation of nonlinear optics not only include the finding of nonlinear phenomena effects, the study of their mechanism and rules, the development of new nonlinear optical technology and the finding of new materials, but also include applications of nonlinear optical effects and techniques in every related field. The thermal self-defocusing effect and reverse saturable absorption properties of nickel one- nuclear complexes have been testified. Moreover, The thermal self-defocusing effect and reverse saturable absorption properties can lead to optical limiting, which can be used in optical limiting device. The thermal self-defocusing effect of one of nickel one- nuclear complexes C12H18N2O2Ni solution has been measured by Z-scan technique, the experimental result shows that the sample has reverse saturated absorption property under the three laser wavelengths that were usedin our experiment. It's well known that both thermal self-defocusing effect and reverse saturable absorption can lead to optical limiting. It is found that Nickel one- nuclear complexes C12H18N2O2Ni solution has optical limiting effect under those waves and that the critical value of optical limiting reduces with the decrease of laser wavelength. Further more, the effect of optical limiting is very good and the critical value is very low, so it's a new optical limiting material with great potential application value.The optical limiting properties nickel one- nuclear complexes HiC22N4H24 solution under CW laser has been studied, as well as nonlinear properties under pulse laser have been studied by Z-scan technique. Three curves of peak followed by valley using the single beam z-scan technique were obtained. According to M.Sheik-bahae's theory the sample has a negative nonlinear refractive index under 1064 nm pulse laser.It was determined as 6.5 x 10-21 m2/W. Meanwhile, the minimum value of normalized transmittance of z-scan curves without aperture are found at the focus, and indicate that nickel one- nuclear complexes have nonlinear absorption properties. Rez of themhave been calculated. The nonlinear refractive index of these two of nickel one- nuclear complexes were determined as 6.95 X 10-11 m2/ W and 3.466 X 10-10m2/W according to the experimental data of Z-scan curve under 488.0nm laser. The value of nickel one-nuclear complexes is 4~5 orders of magnitude lager than some ordinary inorganic materials. These materials would have a good prospect in optical limiting applications. At last, the reason of nonlinear refractive index in these two materials were discussed. We anticipate that we may make optical limiting devices which are useful both on pulse laser and on continuous laser. And we may modulate nickel one-nuclear complexes' optical and thermal properties by designing molecule structures so as to make it a promising organic material.