Irradiation Effect on Second Harmonic Generation of Dyes Doped KDP Crystals

Most irradiation studies in the hydrogen bonded ferroelectrics have been concentrated on the transient defects induced by ionising radiation, such as ultraviolet （UV） light, where the defects are closely related to the optical properties. But heavy ion beam irradiation effects have rarely been studied. The structural, optical, and non-linear optical properties of the doped crystals were analyzed with the characterization studies, such as powder XRD, UV-Visible and second harmonic generation （SHG） measurements, respectively. The results for doped KDP crystal were compared with the results of the pure KDP crystals. The experiment results showed that Li^3＋ irradiation leads to the development of a well-defined surface H peak in dye doped KDP crystals. The stability of KDP single crystal was improved by doping organic dyes. The nano-islands of dye in KDP were likely to be dissolved and enhance the non-linear optical properties of these materials.

Second Harmonic Generation in Some Donor-Acceptor Substituted Chalcone Derivatives

A series of five chalcone derivatives with different substituents in para and meta posions have been synthesized, and single crystals were successfully grown in aceton solution by slow evaporation solution growth technique (SESGT). Single crystal X-ray studies revealed that all the crystals crystallized in noncentrosymmetric space group with their molecular dipoles perfectly aligned in a direction-favorable for large nonlinear optical effects. Kurtz powder tests revealed that all five materials have second-harmonic-generating properties with maximum efficiencies of approximately 14 times that of urea standard. UV-vis-NIR spectroscopy and thermogravimetric analyses are also presented for all of the reported materials. Among the five chalcones, high quality single crystals of 4-Methoxy-4'-chlorochalcone were grown by SESGT, and its crystalline perection were studied by using a high resolution X-ray diffractometry (HRXRD).

KBa2(PO3)5： Properties and Comparison with Isostructural Polyphosphate Compounds

A noncentrosymmetric polyphosphate compound, KBa2（PO3）5, 1 was prepared and characterized. It features 1D [PO3]∞ chains of condensed [PO4]^（3-） tetrahedral units. The polycrystalline sample of 1 exhibits second harmonic generation（SHG） response, demonstrating that the activity of the title compound is about 0.6 times that of KDP that is comparable to the isostructural RbBa2（PO3）5（2） and KPb2（PO3）5（3）. Additionally, powder X-ray diffraction（PXRD）, thermal analysis, IR spectroscopy, UV-Vis-near-IR diffuse reflectance spectroscopy, and theoretical calculations have been also studied, and the structure and property comparison among this type of polyphosphates are summarized.

Imaging the structure and organization of mouse cerebellum and brain stem with second harmonic generation microscopy

To visualize the structure and organization of the brain is a fundamental requirement in the research of neuroscience. Here, combining with two-photon excitation fluorescence microscopy and transgenetic mouse GAD67,we demonstrate a custom-built second harmonic generation（SHG） microscope to discriminate brain layers and sub regions in the cerebellum and brain stem slices with cellular resolution. In particular, the cell densities of neurons in different brain layers are extracted due to the cell soma appearing as dark shadow on an SHG image.Further, the axon initial segments of the Purkinje cell are easily recognized without labeling, which would be useful for guiding micropipettes for electrophysiology.

Recent advances on the synthesis of Sb(Ⅲ)-based inorganic ultraviolet nonlinear optical materials

Nonlinear optical(NLO)crystals are key components of solid-state lasers and widely used in civilian and military applications.A wide transmission range,a large second harmonic generation(SHG)effect and a suitable bire-fringence are important factors in determining a nonlinear material with excellent performance.Research on ultraviolet(UV)nonlinear optical materials has concentrated on borates,carbonates,and nitrates containing derivative groups,as well as phosphates and sulfates containing tetrahedral groups,as a result of the anionic group theory's influence.In addition,cations have a significant impact on NLO materials according to recent researches.The introduction of lone electron pair cations Sb(Ⅲ)has been proven to be an effective strategy by our group,which could modulate the crystal structures of NLO materials to regulate their linear and nonlinear optical properties.This paper presents a short review of the reported Sb(Ⅲ)-based UV-NLO materials.Also,it gives an overview of the role played by different synthetic methods in the synthesis process of Sb(Ⅲ)-based UV-NLO materials and how to solve the difficult problems including oxidation and hydrolysis.This work will offer some synthetic concepts for investigating the subsequent class of high-performance UV nonlinear materials.

希夫碱系化合物的合成及SHG效应

通过芳胺与芳醛的缩合反应，合成了１２个希夫碱系有机化合物，测试了它们的紫外－可见吸收曲线，结果表明：１２个希夫碱系有机化合物的最高吸收波长都在紫外区内．随着芳环（Ａ）取代基供电性的增加，芳环（Ｂ）取代基吸电性的增加，希夫碱系有机化合物的吸收波长红移，采用固体粉末方法测试了合成产品的ＳＨＧ效应，结果发现其中４个品种具有ＳＨＧ活性．

NONLINEAR OPTICAL PROPERTIES OF A-SHAPED NITROPYRIMIDINE DERIVATIVES AND ITS POLYMERIC FILMS

Three A-shaped nitropyrimidine derivatives with benzyl or furfuryl as bridge havebeen synthesized. They possess shorter absorption wavelengths (λ_(cut-off))<400 nm) andhigher βμ values (around 10^(-46) esu). The second order nonlinear optical coefficient d_(33) ofpoled BNPMOPMDA/PMMA doped film is 1.2-2.0×10^(-9) esu obtained by in-situ SHGmeasurements. It can be expected that the chromophore-functionalized polymer containinghigher number density of synthesized chromophore as side chain will be the potential blue-light transparent frequency doubling materials.

Two Low-temperature Phase Transition Compounds Based on Quinuclidine Derivatives with Fluorescence

Two phase transition materials[iPrQ]2MnBr4(1,iPrQ=N-isopropyl-quinuclidinium)and[iPrQ]_(2)MnCl_(4)(2)were synthesized and characterized.Dielectric measurements and differential scanning calorimetry showed that the two compounds underwent reversible phase transitions at ca.–47 and–37℃,respectively.Variable-temperature single-crystal X-ray diffraction suggested that the two compounds underwent the same phase transitions from space group C2/c to Cc but at different temperature.The variable crystal structures indicated that the structural phase transitions of the compound were ascribed to the torsional movement of quinuclidine ring and the disappearance of the c-slide plane.The second harmonic generation(SHG)response further proved this structural phase transition.Fluorescence tests showed that the two compounds have strong fluorescence.The strong variations in dielectric anomalies make compounds 1 and 2 suitable for promising switchable dielectric materials.