【作者】 王玉华；

【导师】 顾玉宗；

【作者基本信息】 河南大学 ， 光学， 2004， 硕士

【摘要】 镍及其金属配合物不仅对于化学科学研究具有重要意义，而且在技术领域也有着广泛的应用，镍单核类配合物所具有的高对称性和独特的电子结构也引起了光谱学家和理论化学家的广泛兴趣。本论文的工作即致力于对镍单核配合物的光学非线性和限幅特性的研究。 1989年M．Sheik-bahae等人提出了单光束Z扫描技术，由于该方法具有实验装置简单、结果易于分析、灵敏度高等优点，因此该方法一经提出便受到广泛关注。现在Z扫描技术已经发展成为测量非线性特性的一种重要手段。 非线性光学具有广泛的应用范围，丰富的研究内容，我们对其主要现象及效应进行了简单概述。非线性光学的主要研究不但在于非线性光学现象与效应的发现及它们产生的机理和规律性的研究、非线性光学新技术的发展和新材料的发现，而且注重非线性光学效应与技术在各有关领域中的应用。我们通过研究证明镍单核配合物具有热自散焦和反饱和吸收效应，并且这两种效应都会引起光限幅，可据此特性制成光限幅器件。我们用单光束Z扫描技术对镍单核配合物C₁₂H₁₈N₂O₂Ni溶液进行了测量，结果表明样品具有热自散焦效应。反饱和吸收特性研究结果表明它在三个波长下均呈现出反饱和吸收效应。众所周知，热自散焦效应和反饱和吸收效应都能导致光限幅。实验结果也表明：镍单核配合物C₁₂H₁₈N₂O₂Ni溶液在三个波长下均具有光限幅特性，限幅阈值随着波长的减小而减小；其光学限幅效果好且限幅阈值低，是一种有较大潜在应用价值的新型光限幅材料。 我们不但研究了镍单核配合物对连续光的限幅特性，还利用单光束Z扫描技术研究了它们在脉冲激光作用下的非线性特性。测得一种镍单核配合物N_iC₂₂N₄H₂₄溶液的闭孔Z扫描曲线是先出现峰值后出现谷值，依据M．Sheik-hahae河南大学光学专业2000级硕士论文等的理论，这种镍单核配合物在波长为IO64nm的脉冲激光作用下呈现负的非线性折射率。同时开孔Z扫描曲线在焦点处出现透过率的最小值，表明它具有非线性吸收特性，其非线性折射率为6.5、10一，，mZ/w;我们还利用归一化透过率曲线算得了这两种镍单核配合物的三阶非线性极化率的实部。从Z扫描曲线的实验数据处理得到这两种镍单核配合物材料在488.Onm的连续光作用下的非线性折射率分别为6.95 xlo一‘’mZ/w和3.4“x 10一’“澎/w，其值比通常的无机材料大4一5个数量级，是一种很有应用前景的新型光学限幅材料。同时，对它们具有的非线性折射率的物理机制进行了分析。我们预期可以利用它们制成对连续光和脉冲光都有限幅效果的光限幅器材料。并且镍单核类化合物可以通过设计分子的结构来调节介质的光学和热学性质，是一类具有良好应用前景的有机材料。更多还原

【Abstract】 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.更多还原