【作者】 程培红；

【导师】 顾玉宗； 莫育俊；

【作者基本信息】 河南大学 ， 光学， 2004， 硕士

【摘要】 金属有机化合物是一种很有前途的非线性光学材料。它的结构中含有较强的π电子共轭体系，并且有机配体与中心原子间的电子转移，大大提高了其非线性极化率。探索金属有机化合物的结构特征，研究其光学特性具有非常重要的意义，它可以指导我们合成更有价值的金属有机化合物，并能为实际应用提供有益的帮助。本文的工作主要是利用单光束Z扫描技术研究了三种新型金属有机化合物的三阶非线性光学特性，并且利用拉曼光谱技术探索了这些化合物的结构振动信息，试图从结构方面更深入的了解其非线性光学性质。论文共分六章，其主要内容概括为三个部分： 第一部分，即论文的第一章，简单介绍了非线性光学发展的现状以及非线性光学的现实应用和意义，着重介绍三阶非线性光学效应，用Z扫描方法测量三阶非线性光学系数的方法和理论。介绍了拉曼光谱和表面增强拉曼光谱的基本概念，表面增强拉曼光谱的发展和应用，以及拉曼光谱仪的基本知识。 第二部分，即论文的第二、三、四章，首先，我们利用连续激光的457.5nm、488nm、514.5nm三个波长Z扫描方法研究了NiL₂、CuL₂、PdL₂三种新型化合物的热致三阶非线性光学特性，分别计算了三种化合物在各个波长的热光系数。结果表明，其热光系数与激发波长、在该波长下的吸收、及化合物结构都有一定关系。其次，利用Z扫描方法研究了这三种金属有机化合物在皮秒脉冲激光的1064nm波长下的三阶非线性光学特性。根据实验曲线计算了它们在1064nm下的三阶非线性折射率和非线性吸收系数，三种化合物都具有自聚焦特性，并且在该波长下，三种化合物均具有双光子吸收，最后，以皮秒脉冲的532nm为激发波长，采用Z扫描方法，研究了三种金属有机化合物的非线性折射和非线性吸收性质，在该波长下三种化合物仍然表现为自聚焦特性，且其吸收为反饱和吸收。通过曲线拟合，得出了它们的激发态吸收截面。并且与三种金属有机化合物的结构联系，分析了其三阶非线性光学特性与分子结构之间的关系。 第三部分，即论文的第五章，我们以632.8nln为激发波长研究了NILZ、CuLZ和PdL:三种新型金属有机化合物粉末的正常拉曼光谱，并且以脉冲激光刻蚀法制备了水银胶，以其为衬底研究了三种化合物溶液在其上的表面增强拉曼光谱，通过对其拉曼光谱进行了初步指认，了解由于中心原子的不同，三种金属有机化合物分子振动的相同和区别。 另外，我们在第六章里进行了讨论和总结。更多还原

【Abstract】 Organometallic Complexes are promising nonlinear optical materials. Their molecule structures have strong π electron conjugated systems and electron transition between organic ligands and center metal atoms, which result an enhancement of their nonlinear polarizabilities. To probe structural characters of organometallic complexes and to investigate their optical properties are significant, which can direct us to synthesize more valuable organometallic complexes for practical applications in nonlinear optics. The principal work in this paper is to investigate the third-order nonlinear optical properties of three new organometallic complexes with Z-scan technique, and study the molecule structural vibration of these complexes .in order to further understand their nonlinear optical characters There are six chapters in this paper, which can be divided into three sections:In the first section, i.e. chapter one, the current status of the development and practical applications of nonlinear optics are introduced briefly The third-order nonlinear optical effect is introduced particularly. In addition, the theory and the method of Z-scan technique are described for the measurement of nonlinear optical coefficients The basic concept of the Raman spetroscopy and Surface Enhanced Raman Scatterring spectroscopy, the development and application of Surface Enhanced Raman Scatterring spectroscopy and principal knowledge of Raman spectrometer are also presented in the paper.In the second section, i.e. chapter two, three and four, firstly, the thermal induced third order nonlinear optical characters of three organometallic complexes (NiL2, CuL2, PdL2) are studied by the Z-scan technique, thermaloptical coefficients of the three compounds excited under different laser wavelengths are calculated The results showthat the thermaloptical coefficients are dependent on excitation wavelengths, the absorptions under these wavelengths and molecular structures of these compounds. Secondly, the third order nonlinear optical properties of these compounds are studied under the excitation of ps pulsed laser with the wavelength of 1064nm using Z-scan technique, nonlinear refractive indices and nonlinear absorption coefficients are calculated according to the Z-scan experiment curves of the compounds. All the three compounds have self defocusing characters and two photon absorptions. Lastly, nonlinear refraction and absorption properties of these compounds are studied by Z-scan technique under the excitation of ps pulsed laser with the wavelength of 532nm The self defocusing and reverse saturation absorption are found in these compounds. Excited state absorption cross sections are obtained through Z-scan curve fitting. Moreover, the relation between the third order nonlinear optical characters of the compounds and their molecular structures is analyzed by connecting the experimental result with molecular structures.In the third section, i.e. chapter five, the normal Raman spectra of NiL2, CuL2, PdL2 powder are studied under the excitation of laser with the wavelength of 632.8nm And aqueous silver colloid is prepared by pulsed laser ablation, from which the surface enhanced Raman spectra of the three compounds are obtained. After preliminary assignment, the identical and different features of vibration of the compounds due to the different central metal atoms are analyzed .In addition, discussions and conclusions are made in the sixth chapter.更多还原