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101.
Fresnel波带片有多个焦点,作为单色器波长选择元件使用时会受到高级衍射的影响。而Gabor波带片只有一个焦点,有更好的聚焦特性,但制作难度较大,准随机点阵二值化Gabor波带片概念的提出则解决了这个问题。介绍了准随机点阵二值化Gabor波带片的设计,并利用优化的程序分别对Fresnel波带片和准随机点阵二值化Gabor波带片的聚焦特性进行了模拟计算,通过对计算结果进行分析比较,发现准随机点阵二值化Gabor波带片具有抑制高阶衍射的特性。 相似文献
102.
稀土掺杂的(K, Sr)Cl·SiO2复合凝胶的荧光性能 总被引:1,自引:0,他引:1
采用sol gel法制备了单掺铕及共掺铕、铈的(K,Sr)Cl·SiO2复合凝胶,研究了复合凝胶的荧光性能。根据荧光测试结果,复合凝胶中,Eu3+在没有还原剂的作用下,可以与基质作用形成还原态的Eu2+,复合凝胶表现出相应的Eu2+荧光性能;研究认为,Ce3+,Eu3+共掺杂时,复合凝胶激发光谱与发射光谱峰位基本不变,但强度有所不同。330nm处的激发光谱明显增强,且发射光谱随Ce3+的掺杂量增加而增强。当Ce3+掺杂浓度为3.0%(原子分数)时,复合凝胶具有最大的荧光发射强度,表明Ce3+具有很好的敏化作用。在Ce3+,Eu3+共掺杂复合凝胶体系中,复合凝胶荧光强度增大的原因既可能是电子转移过程,也可能是Ce3+→Eu2+的能量传递过程所致。 相似文献
103.
Synthetic,Optical and Theoretical Study of Alternating Ethylenedioxythiophene–Pyridine Oligomers: Evolution from Planar Conjugated to Helicoidal Structure towards a Chiral Configuration 下载免费PDF全文
Floris Chevallier Marina Charlot Florence Mongin Benoît Champagne Edith Franz Koen Clays Mireille Blanchard‐Desce 《Chemphyschem》2016,17(24):4090-4101
A series of alternating 3,4‐ethylenedioxythiophene–alkynylpyridine oligomers (DA)n with increased solubility are synthesized and their photophysical properties and nonlinear optical properties are investigated. Their quadratic polarizabilities are determined from hyper‐Rayleigh scattering experiments to obtain information on their conformations in solution. These chromophores, based on the alternation of electron‐rich (D) and electron‐deficient (A) moieties, exhibit optical properties that arise from the combination of dipolar and helicoidal features in the (DA)n homologue series where n=1–4. The transition from dipolar conjugated planar structures (n=1, 2) to helicoidal structures (n=3, 4) is clearly evidenced by results from symmetry‐sensitive second‐order nonlinear optical experiments. This suggests an approach towards highly efficient chiral chromophores for second‐order nonlinear optics. Interestingly, this structural evolution also has significant impact on the photophysical properties: both absorption and fluorescence emission show bathochromic and hyperchromic shifts with increasing number of repeating units in the dipolar planar derivatives (n=1–2) but show saturation effects in the helicoidal structures (n=2–4). In addition, the helicoidal structures show sizeable two‐photon absorption at 700–750 nm (40–100 GM) for compounds lacking either electron‐donating or electron‐withdrawing substituents. 相似文献
104.
Abstract : Second‐order nonlinear optical (NLO) dendrimers with a special topological structure were regarded as the most promising candidates for practical applications in the field of optoelectronic materials. Dendronized hyperbranched polymers (DHPs), a new type of polymers with dendritic structures, proposed and named by us recently, demonstrated interesting properties and some advantages over other polymers. Some of our work concerning these two types of polymers are presented herein, especially focusing on the design idea and structure–property relationship. To enhance their comprehensive NLO performance, dendrimers were designed and synthesized by adjusting their isolation mode, increasing the number of the dendritic generation, modifying their topological structure, introducing isolation chromophores, and utilizing the Ar‐ArF self‐assembly effect. To make full use of the advantages of both the structural integrity of dendrimers and the convenient one‐pot synthesis of hyperbranched polymers, DHPs were explored by utilizing low‐generation dendrons as big monomers to construct hyperbranched polymers. These selected works could provide valuable information to deeply understand the relationship between the structure and properties of functional polymers with dendritic structures, but not only limited to the NLO ones, and might contribute much to the further development of functional polymers with rational design. 相似文献
105.
Dr. Qi Wei Jia‐Jia Wang Dr. Chao He Prof. Dr. Jian‐Wen Cheng Prof. Dr. Guo‐Yu Yang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(31):10759-10762
A new borate LiBa3(OH)[B9O16][B(OH)4], which combines the uniform porosity of open‐frameworks with the extraordinary NLO properties of borates, has been obtained under hydrothermal conditions by using mixed lithium and barium ions as templates. The framework displays an acs‐type net with large 21‐ring channels. The second harmonic generation (SHG) measurement shows that it is a type I phase‐matchable material with a strong SHG signal intensity about 3.1 times that of KDP (KH2PO4). UV/Vis–NIR diffuse reflectance analysis indicates that the compound has a wide transparency range with the short‐wavelength absorption edge below 200 nm. These characteristics reveal that the compound is a promising deep‐UV nonlinear optical material. 相似文献
106.
Paul Kautny Dorian Bader Dr. Berthold Stöger Prof. Dr. Georg A. Reider Prof. Dr. Johannes Fröhlich Dr. Daniel Lumpi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(52):18887-18898
To shed light on intramolecular charge‐transfer phenomena in 1,2,3‐triazole‐linked materials, a series of 1,2,3‐triazole‐linked push–pull chromophores were prepared and studied experimentally and computationally. Investigated modifications include variation of donor and/or acceptor strength and linker moiety as well as regioisomers. Photophysical characterization of intramolecular charge‐transfer features revealed ambipolar behavior of the triazole linker, depending on the substitution position. Furthermore, non‐centrosymmetric materials were subjected to second‐harmonic generation measurements, which revealed the high nonlinear optical activity of this class of materials. 相似文献
107.
The delay in the nonlinear response of matter to intense laser pulses has been studied since a long time regarding its nuclear contribution. In contrast, the electronic part of the nonlinear response in wide-band-gap dielectrics, which is usually dominant, is not well explored regarding its delay, and previous studies have revealed that the timescale is below 1 fs. Here, the influence of delay times on the recently introduced method of subcycle-resolved probe retardation measurements is investigated using a simulation. In the model assumed, the electronic nonlinearity is divided into the third order Kerr effect and the plasma contribution due to conduction band population in the strong laser field. In the regime of close-to-collinear pump-probe geometries, the probe retardation shows both π- and 2π-oscillations in the pump-probe delay. Sub-femtosecond delay times influence the phase of the oscillations significantly, but it remains difficult to distinguish the influence of the Kerr response from the plasma contribution. 相似文献
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