蒽二酮类化合物的合成及结构-非线性光学性能关系的研究

设计合成了6个新的蒽二酮类化合物,用紫外可见吸收光谱、傅里叶变换红外光谱、1H核磁共振和元素分析表征了结构.采用飞秒激光,运用简并四波混频法,研究了化合物在非共振状态下的三阶非线性光学性能.它们的三阶非线性光学极化率χ(3)为2.62～3.55×10-13esu,非线性折射率n2为4.82～6.52×10-12esu,分子二阶超极化率γ为2.57～3.25×10-31esu,响应时间τ为91～116fs.探索了化合物的分子结构对三阶非线性光学性能的影响.增长共轭链,形成供吸供构型,增大取代基的供电子能力,提高共轭体系的共平面程度等因素有利于获得较大的三阶非线性光学性能.     

噻二唑衍生物的三阶非线性光学性能与合成

设计合成了7个新的噻二唑衍生物,用UV、IR1、H NMR和元素分析进行了表征。采用飞秒激光,运用简并四波混频法,研究了衍生物在非共振状态下的三阶非线性光学性能。它们的三阶非线性光学极化率χ(3)为3.75~4.18×10-13esu,非线性折射率n2为6.90~7.68×10-12esu,分子二阶超极化率γ为3.75~4.26×10-31esu,响应时间为101~115 fs。探索了衍生物的分子结构对三阶非线性光学性能的影响。引入离域能小的芳杂环,增长共轭链,形成吸供构型,增大取代基的供电子能力,提高共轭体系的共平面程度等因素有利于获得较大的三阶非线性光学性能。     

Y型均三嗪类衍生物三阶非线性光学性质研究

采用密度泛函理论B3LYP/6-31+G*方法对含Y型均三嗪类衍生物的6个分子(Y1-Y6)进行几何构型优化,对其最优构型采用TD-DFT(TDB3LYP/6-31+G*)计算电子吸收光谱,用有限场FF方法及自编程序计算三阶非线性光学（NLO）性质。结果表明,6个含Y型均三嗪类有机分子的三阶非线性光学系数g值为1010数量级个原子单位(10-30 esu),显示出良好的三阶非线性光学性能。在其三支链的末端引入不同的推、拉电子基团（Y2→Y6）,对其电子光谱和三阶非线性光学响应具有明显的影响。引入强供电子基团,g增大幅度较大,有利于改善体系的三阶非线性光学性质,从而可获得良好的非线性光学材料。     

蒽二酮类化合物的合成及结构-非线性光学性能关系的研究

设计合成了6个新的蒽二酮类化合物,用紫外可见吸收光谱、傅里叶变换红外光谱、1H 核磁共振和元素分析表征了结构.采用飞秒激光,运用简并四波混频法,研究了化合物在非共振状态下的三阶非线性光学性能.它们的三阶非线性光学极化率χ(3)为2.62～3.55×10－13 esu,非线性折射率n2为4.82～6.52×10－12 esu,分子二阶超极化率γ为2.57～3.25×10－31 esu,响应时间τ为91～116 fs.探索了化合物的分子结构对三阶非线性光学性能的影响.增长共轭链,形成供吸供构型,增大取代基的供电子能力,提高共轭体系的共平面程度等因素有利于获得较大的三阶非线性光学性能.     

Y型均三嗪类衍生物三阶非线性光学性质研究

采用密度泛函理论B3LYP/6-31+G*方法对含Y型均三嗪类衍生物的6个分子(Y1-Y6)进行几何构型优化,对其最优构型采用TD-DFT (TDB3 LYP/6-31+G*)计算电子吸收光谱,用有限场FF方法及自编程序计算三阶非线性光学(NLO)性质.结果表明,6个含Y型均三嗪类有机分子的三阶非线性光学系数γ值为1010数量级个原子单位(10-30 esu),显示出良好的三阶非线性光学性能.在其三支链的末端引入不同的推、拉电子基团(Y2→Y6),对其电子光谱和三阶非线性光学响应具有明显的影响.引入强供电子基团,γ增大幅度较大,有利于改善体系的三阶非线性光学性质,从而可获得良好的非线性光学材料.     

基于螺旋单电子模型的手性分子的三阶非线性极化率

本文从螺旋手性分子单电子模型出发,推导手性分子的三阶光学非线性,给出螺旋手性分子三阶极化率张量元的解析表达式,并讨论分析了实际的螺旋分子的极化率张量的非零元素.     

半花菁LB膜的三阶非线性特性

本文利用Z扫描测量技术首次对半花菁LB膜的三阶非线性光学特性进行了研究.实验结果表明,LB多层膜中的半花菁分子具有较高的三阶非线性折射率n²=2.0×10^-8(esu),这主要是半花菁分子中π电子体系的贡献,并且由于532nm在其Q吸收带内,引起三阶非线性的共振增强效应,实验数据与理论拟合结果符合得很好.半花菁LB膜的三阶非线性的响应时间在30ns以内.     

吐昔烯衍生物分子的电子光谱与非线性光学性质

采用含时密度泛函理论(TDDFT)B3LYP对5个吐昔烯及其衍生物分子的吸收光谱进行理论计算。结果表明,该5个分子的吸收波长在281—307 nm范围内,属于近紫外区。使用有限场(FF)方法理论计算5个化合物分子的非线性光学(NLO)性质。结果显示,吐昔烯分子引入烷氧基将明显增大二阶和三阶非线性光学性质（b0和 值）,此类化合物分子的三阶非线性光学性质明显优于二阶非线性光学性质。     

吐昔烯衍生物分子的电子光谱与非线性光学性质北大核心CSCD

采用含时密度泛函理论（TDDFT）B3LYP对5个吐昔烯及其衍生物分子的吸收光谱进行理论计算．结果表明,该5个分子的吸收波长在281～307nm范围内,属于近紫外区．使用有限场（FF）方法理论计算5个化合物分子的非线性光学（NLO）性质．结果显示,吐昔烯分子引入烷氧基将明显增大二阶和三阶非线性光学性质（β0和Y值）,此类化合物分子的三阶非线性光学性质明显优于二阶非线性光学性质．     

足球烯分子三阶非线性光学性质的研究

报道了有关足球烯分子甲苯溶液中简并四波混频实验.测量出足球烯C_(70)分子和C_(60)分子的三阶超极化率张量y_(1111)分量分别为1.2×10~(-30)esu和4.0×10~(-31)esu.对应于固体样品的三阶非线性光学系数X_(1111)分量分别是2.5×10~(-8)esu和8.5×10~(-9)esu.此结果表明了足球烯分子是现有的非线性光学材料中具有较大三阶非共振电子极化率材料之一.文中还利用自由电子模型解释了非线性光学极化率的起源.     

Polaron effects on the optical absorption coefficients and refractive index changes in a square quantum well

The linear and nonlinear optical absorption coefficients and refractive index changes are obtained by using the compact density-matrix approach and an iterative procedure. With typical semiconducting GaAs materials, the linear, third-order nonlinear, total optical absorption coefficients and the optical refractive index have been examined. We find that the polaron effect has an important influence on the linear, third-order nonlinear, and total absorption coefficients as well as the refractive index changes.     

有机聚合物的非线性光学

有机聚合物是一类非常重要的非线性光学材料,这是因为它在光通信和高密度光存储等高技术领域中有良好的应用前景。有机聚合物的非线性光学性质是过去２０年来理论和实验的重要研究课题。文章在简要介绍非线性光学之后,着重论述了有机聚合物光学非线性的来源和这些材料中二阶、三阶非线性光学效应及非线性光吸收的特点。最后,简要介绍了作者在有机聚合物非线性光学研究中几个近期结果,如“全光极化、三阶光学非线性的激发态增强、     

Large third-order optical nonlinearities in brilliant green solutions induced by CW He-Ne laser

Laser induced third-order nonlinear optical responses of Brilliant Green solution (which belongs to triphenylmethane organic dye group) was investigated by utilizing single beam Z-scan technique using a continuous wave He-Ne laser at the wavelength of 632.8 nm. It was observed that the material exhibits self-defocusing and saturation absorption type optical nonlinearity behavior. The measurements of the real and imaginary parts of the third-order nonlinear optical susceptibility were carried out at several incident laser irradiations and different dye concentrations. It was found that the increase in any of the incident laser intensity or solution concentration leads to the linear increase of the nonlinear refractive index. The obtained values of the third-order nonlinearities of Brilliant Green solutions are amongst the highest reported CW regimes, to the best of our knowledge. This study shows a great potential of the Brilliant Green for the application in nonlinear optical devices.     

Relationship between third-order nonlinear optical properties and magnetic interactions in open-shell systems: a new paradigm for nonlinear optics

Although most third-order nonlinear optical (NLO) materials are closed-shell singlet systems, this Letter theoretically shows that the third-order NLO properties are drastically enhanced in symmetric open-shell diradical systems with intermediate diradical character and further reveals that this enhancement is associated with the ferromagnetic and antiferromagnetic interactions. This new paradigm opens up a promising area for designing new third-order NLO materials.     

聚（2，5－二丁氧基）苯撑的三阶非线性光学性质

报道了一种新的同可溶性好的，具有连苯结构的共轭有机聚合物：聚（２，５－二丁氧基）苯撑（简称ＰＰＰ），采用四波混频方法测量了它在５３２ｎｍ和１０６４ｎｍ处的三阶非线性光学系数，由此推算了非线性折射率，并讨论了材料的优质因子，指出了材料最适用的光波段。     

新型Ru配合物三阶非线性光学性质的Z-扫描研究

通过Z-扫描的实验方法测量了几种新型的Ru配合物在460nm处的三阶非线性折射率n₂和非线性吸收系数β,并由此计算出它们的三阶非线性系数χ⁽³⁾.分析了分子结构对其三阶非线性光学性质的影响. 关键词：     

Enhanced nonlinear optical responses of materials: Composite effects

We review recent theoretical progress in understanding physical processes of composite effects on enhanced third-order nonlinear optical responses of various kinds of the recently-proposed nonlinear optical materials, namely, colloidal nanocrystals with inhomogeneous metallodielectric particles or a graded-index host, metallic films with inhomogeneous microstructures adjusted by ion doping or temperature gradient, composites with compositional gradation or graded particles, and magneto-controlled ferrofluid-based nonlinear optical materials.     

Third-Order Nonlinear Optical Susceptibility of Indium Phosphide Nanocrystals

InP nanocrystals synthesized by refluxing and annealing of organic solvent are determined from XRD measurements to have an averse granularity of 25 nm. The nonlinear optical properties of the InP nanocrystals studied by using laser Z-scan technique with 50 ps pulses at 532nm are found to reveal strong nonlinear optical properties and two-photon absorption phenomenon. Also, the nonlinear absorption coeffcient, the nonlinear refractive index and the third-order nonlinear optical susceptibility are determined by experiments, in which the nonlinear refractive index is three orders of magnitude larger than that of bulk InP.     

Picosecond pump-probe measurement of bandgap changes in SiO2/TiO2 one-dimensional photonic bandgap structures

A picosecond pump-probe nonlinear optical measurement is performed in SiO2/TiO2 one-dimensional photonic bandgap structures fabricated by a solgel method. Both high and low band edges were examined by varying the probe wavelengths and angle tuning was also employed to further clarify the mechanism of a nonlinear optical response. The third-order nonlinear optical response in one-dimensional photonic bandgap structures that comprise TiO2 films is responsible for the nonlinear optical transmissions at both bandgap edges, with an 8% decrease at the low-energy edge and a 4.5% increase at the high-energy edge for a 355 nm pump intensity of 430 MW/cm2.     

Polaron effects on linear and nonlinear optical properties of a two-electron quantum dot

The linear and nonlinear optical properties of parabolic quantum dots in which two electrons interact with each other through both coulomb repulsion and longitudinal-optical phonon are studied by using the matrix diagonalization method. With typical semiconducting GaAs-based materials, the linear, third-order nonlinear, total optical absorption coefficients and the optical refractive index have been examined. The effects of different electron-phonon coupling strengths on the linear and nonlinear optical properties are also predicted.