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.     

A new class of conjugated molecules with large second order polarizability

We report measurements of the second order polarizability β in a new class of conjugated molecules. A representative member of this class is H₃C-NC₅H₄-CH-CH-C₆H₄-O. The measured value of β, 10^-27 esu, for this molecule is larger than any other known value for molecules with the same length and number of π-electrons. We present a discussion of this high value in terms of resonating chemical structures and hyperconjugation.     

有机大分子三阶非线性光学材料的研究进展

根据分子结构特征评述了各类有机大分子三阶非线性光学材料结构与性能的关系。概述了三阶非线性光学性能的计算。分析了材料分子设计原理和展望了应用前景。     

The interaction polarizability of two hydrogen molecules

The incremental polarizability which occurs when two hydrogen molecules interact has been calculated by the ab initio SCF method using a [3s, 2p] gaussian basis set. Results are reported for various separations and orientations. Where symmetry allows, the polarizabilities are compared with those of the helium diatom. The general shapes of the curves are similar, though they differ in detail.     

可溶性聚噻吩甲烯包覆碳纳米管的三阶非线性光学响应

采用原位聚合的方法合成了聚(3-己基噻吩)-2,5-二(4-羟基-3-甲氧基苯甲烯)包覆的多壁碳纳米管(PHTHMOBQ/MWNTs). 荧光光谱分析表明, PHTHMOBQ/MWNTs复合体中, 碳纳米管与共轭聚合物PHTHMOBQ之间形成光致电子转移体系, 使得π电子离域程度增加, 并且导致荧光量子效率降低. 根据E_g与入射光子能量hν的关系, 拟合了PHTHMOBQ/MWNTs薄膜的光学禁带宽度. 发现随着碳纳米管含量的增加, E_g逐步减小. 采用简并四波 关键词： 共轭聚合物 碳纳米管 光致电子转移 三阶非线性光学效应     

Temperature dependence of polarizability of diatomic homonuclear molecules

The temperature dependence of the mean polarizability of the H₂, N₂, and O₂ molecules are calculated in the temperature range up to 2000 K. The values of polarizability derivatives of these molecules from the literature are used in the calculation. The temperature dependence of the mean polarizability of molecules is represented in the form of a second degree polynomial.     

Gigantic nonlinear optical polarizability of semiconductor microcrystallites

We analyze theoretically the nonlinear optical properties of semiconductor box so small that quantum confinement effect works in all three dimensions. It is shown for the first time that the third order optical polarizability of an assembly of such quantum boxes is enhanced by a number of unit cells in the box through the effect of the giant oscillator strength when the box size satisfies the conditions given in terms of size-quantization energy, exciton binding energy, interaction energy of two excitations and the off-resonance energy. Microcrystallites of CuCl look a promising material to observe this effect.     

CuO薄膜的三阶非线性光学特性研究

采用脉冲激光沉积技术在Si(100)和熔石英基片上制备了单相的CuO薄膜.通过X射线衍射仪,拉曼光谱仪,场发射扫描电镜和紫外可见光光度计对薄膜的结构,表面形貌和光学性质进行了表征. 场发射扫描电镜结果表明CuO薄膜中晶粒排列致密且分布均匀,其尺寸约为45nm.结合飞秒激光(800nm,50fs)和Z扫描方法测量了薄膜的三阶非线性光学特性,结果表明CuO薄膜具有超快的非线性光学响应且非线性折射率和非线性吸收系数均为负值,其大小分别为-3.96×10^-17 m^{2< 关键词： CuO薄膜 Z-扫描')" href="#">Z-扫描 三阶光学非线性}     

Third-order optical susceptibility of small metallic particles

Summary We present a tight-binding model for the linear and non-linear optical properties of small metal particles, which takes into account both size and matrix effects. We show that the surface states and the dielectric medium embedding the particles determine the properties of the microcrystals; in particular, we prove that the shallow-lyingd-band plays a crucial role in noble-metal particles. As an example, we calculate the third-order susceptibility and the phase-conjugated signalfor gold clusters made of several hundred atoms. A good agreement with experimental results is obtained.     

Third-order aberration analysis of tilted-pupil optical systems

The aberration field of an optical system with a tilted pupil is explored through expanding the vector expressions of the third-order wavefront aberrations. First, the vector forms of the wavefront aberrations are modified to obtain the aberration expressions with the pupil tilted; full field displays of coma and astigmatism in this situation are given. Then, the third-order aberration formulas with the pupil decentered and tilted simultaneously are derived and discussed. Finally, an example is taken to certify the validity of aberration distribution properties.     

新型偶氮苯衍生物的三阶非线性光学特性

本文以30 ps的脉冲激光为激发光源,用Z扫描技术研究了偶氮苯类材料4-羟基-4’-羧基偶氮苯(BN)和N-(3,4,5-辛氧基苯基)-N’-4-[(4-羟基苯)偶氮苯]1,3,4-恶二唑(AOB-t8)及金属复合物(Au/AOB-t8)的三阶非线性光学性质,并从理论上进行了分析和计算.结果表明,AOB-t8的三阶非线性极化率是BN的1.38倍,其非线性光学效应的增大是由共轭链增长、大π键增多引起的.结果同时给出,AOB-t8的三阶非线性极化率是其与金纳米颗粒复合物的4.7倍,这种与金属复合产生的非线性光学效应的减弱是金属引入的局域场效应与有机分子大π键作用之间相互抵消导致的.     

Third-order nonlinear optical studies of new anthraquinone derivatives

Four new donor-acceptor-donor anthraquinone derivatives were synthesized and characterized by UV, IR, ¹H NMR and elemental analysis. Their off-resonant third-order nonlinear optical properties were measured using femtosecond laser and degenerate four-wave mixing technique. The third-order nonlinear optical susceptibilities χ⁽³⁾ were 3.36-3.76 × 10⁻¹³ esu. The nonlinear refractive indexes n₂ were 6.19-6.91 × 10⁻¹² esu. The second-order hyperpolarizabilities γ of the molecules were 3.36-3.76 × 10⁻³¹ esu. The response times were 101-115 fs. The results show that these compounds have potential nonlinear optical applications.     

Third-order aberration analysis of an off-axial optical system

The aberration theory applied to co-axial optical systems is extended to off-axial systems, for which third-order aberration coefficients are considered. The derived aberrations are analyzed using three-dimensional ray bundles, spot diagrams, and image charts, and classified in relation to the system symmetry. This theory is very useful for optical designers, allowing them to clarify the relationship between the structures of off-axial optical systems and the corresponding off-axial aberrations.     

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。     

Conformational dynamics of photoexcited conjugated molecules

Time-dependent photoexcitation and optical spectroscopy of pi-conjugated molecules is described using a new method for the simulation of excited state molecular dynamics in extended molecular systems with sizes up to hundreds of atoms. Applications are made to poly(p-phenylene vinylene) oligomers. Our analysis shows self-trapping of excitations on about six repeat units in the course of photoexcitation relaxation, identifies specific slow (torsion) and fast (bond-stretch) nuclear motions strongly coupled to the electronic degrees of freedom, and predicts spectroscopic signatures of molecular conformations.     

Two-color laser manipulation of single organic molecules based on nonlinear optical response

We theoretically propose two-color laser manipulation with greatly improved efficiency to mechanically manipulate single organic molecules. The present method is based on the nonlinear resonant laser manipulation proposed in a recent study. In the first part, we describe a method to trap single organic molecules that can be more effective than ever before utilizing two-color beams. In the second part, we demonstrate the possibility to selectively “pull” single organic molecules with a particular type of electronic-level scheme by using single-side illumination of traveling light.     

面对称光学系统的初级波像差理论研究

非旋转轴对称光学系统波像差理论的建立有利于理解旋转 轴对称光学系统的装调误差和离轴三反射光学系统等非旋转轴对称光学系统的选型设计. 本文利用旋转轴对称球面光学系统的全口径初级波像差理论推导了子孔径面对称光学系统的初级波像差分布公式, 证明了面对称光学系统中的节点像差理论, 即除球差外的所有初级像差的零值节点偏离视场中心, 而不再是视场的旋转对称函数; 并首次阐述了多零值节点初级非对称像差产生的根源和变化特性. 该理论可以有效指导非对称光学系统初始结构的选择和优化设计过程. 关键词： 面对称 像差 几何光学     

Third-order optical intensity correlation measurements of pseudo-thermal light

Third-order Hanbrury Brown–Twiss and double-slit interference experiments with a pseudo-thermal light are performed by recording intensities in single, double and triple optical paths, respectively. The experimental results verifies the theoretical prediction that the indispensable condition for achieving a interference pattern or ghost image in Nth-order intensity correlation measurements is the synchronous detection of the same light field by each reference detector, no matter the intensities recorded in one, or two, or N optical paths. It is shown that, when the reference detectors are scanned in the opposite directions, the visibility and resolution of the third-order spatial correlation function of thermal light is much better than that scanned in the same direction, but it is no use for obtaining the Nth-order interference pattern or ghost image in the thermal Nth-order interference or ghost imaging.     

Fine-structure fluorescence of conjugated chain molecules

The fine-structure fluorescence spectra of conjugated chain compounds—distyrylbenzene (DSB), its fluorine-substituted derivative (FDSB), 1,4-bis-(5-phenyl-2-oxazolyl) benzene (POPOP), and 1,4-bis-(5-phenyl-2-oxadiazolyl) benzene (PDPDP)—are obtained at 4.2 K using the Shpolskii method. The multiplicity of the spectra is revealed and their vibrational analysis is performed involving Raman scattering data. It is shown that some vibrational frequencies of the fluorescence spectra are common for all the molecules under study, while other frequencies are specific for the spectra of the pairs DSB-FDSB and POPOP-PDPDP. The relation between the spectra of the molecules and their structure is considered.