【作者】 刘军辉；

【导师】 毛艳丽；

【作者基本信息】 河南大学 ， 光学， 2006， 硕士

【摘要】 自从上世纪六十年代激光问世以来,非线性光学得到了很大的发展,它是一门介于基础和应用之间的崭新的学科。随着理论和实践研究的深入,在很多科学领域都得到了广泛的开发和应用。经过长期的理论和实践研究,在对各种非线性光学现象的本质基本弄清楚以后,人们就逐步转向寻找或合成具有特定功能的非线性光学材料的研究。而理想的非线性光学材料要求具有较大的非线性光学极化率、较小的阈值功率以及非常快的响应速度。大量的研究表明有机化合物是一种很有前途的非线性光学材料,可以合成结构中含有较强π电子共轭体系的化合物,配体与中心原子间的电子转移,大大提高了非线性极化率。探索有机化合物的特征,研究其光学特性具有非常重要的意义,可以指导我们合成更有价值的有机化合物,并能为实际应用提供有益帮助。本文的工作主要研究了新合成的两种具有分子对称性的芴类衍生物4-2（-7-（4-氨基苯乙烯基）-9,9-二（2-乙基已基）-9H-芴-2-）乙烯基)苯胺（BASF）和2,7-二（4-甲氧基苯乙烯基）-9,9-二（2-乙基已基）-9H-芴（BMOSF）的三阶、五阶非线性光学特性,并试图从结构方面更深入的了解其非线性光学特性的本质。主要从三个方面进行了研究:第一,利用超短皮秒脉冲研究了其非线性吸收和上转换发光特性。发现它们都具有很强的三光子吸收频率上转换荧光发射特性,实验测出BASF和BMOSF的上转换荧光的波长范围分别是456-775nm和420-670nm,在510nm处的荧光强度与入射光强的三次方成正比。在0.002mol/L的浓度下就有明显的三光子吸收诱导的光限幅效应。通过对实验曲线的拟合得出非线性吸收系数分别为γ=4.34×10^-20cm³/W²和γ=5.92×10^-20 cm³/W²,从而计算出三光子吸收截面分别为σ₃^’=8.4更多还原

【Abstract】 Since the appearance of laser in the early 1960s, nonlinear optics has been developed greatly. It is a new subject between basic subjects and applying subjects. With the deep investigation of theory and application, nonlinear optics has been applied in many fields.People have made the principle of nonlinear optics phenomenon clear through a long basic and practice research, so they begin to look for or synthesize new nonlinear optics materials providing with specific functions. Ideal optical materials provide with big nonlinear polarizability, small power threshold and quick response speed. A great deal of researches have indicated that organic compounds is promising nonlinear optical materials, since they can be synthesized with strongπelectron conjugated systems and electron transition between ligands and central atoms, which result in enhancement of nonlinear polarizability. Exploring organic compounds’characters and researching their optical properties are significant, which can direct us to synthesize more valuable organic compounds for practical applications in nonlinear optics.The principal work in this paper is to investigate the third-order and fifth-order nonlinear optical properties of two fluorene derivatives, which are named as 4-(2-(7- (4-aminostyryl)-9,9-bis(2-ethylhexyl)-9H-fluoren-2-yl)vinyl)benzenamino (abbrevi- ated as BASF) and 2,7-bis(4-methoxystyryl)-9,9-bis(2-ethylhexyl)-9H-fluorene (abb- reviated as BMOSF), and try to further perceive what mostly affects or determine their nonlinear optical characters in the molecule structure, in order to provide references for synthesizing better nonlinear optical materials in the future.Firstly, ps pulse laser is used to investigate the nonlinear absorption and upconversion radiation properties. Strong three-photon absorption frequence upconversion fluorescence emission is found. The three-photon absorption(3PA)更多还原