New side-chain polyurethanes with highly conjugated push–pull chromophores for second order NLO applications

Six new side-chain polyurethanes with large molecular hyperpolarizabilities were synthesized by reaction of ethylenic and/or azo bridged push–pull chromophoric monomers with tolylene 2,4-diisocyanate. The NLO-phores show different conjugation pathway but analogous donor/withdrawing substituents. The chemical and thermal properties of the chromophores and of the polymers were examined. Evaluation of the second order NLO properties was performed by EFISH determination of μβ on the monomers, and by SHG measurements on some amorphous thin films obtained from polymers through spin-coating technique.     

A new stilbazolium salt with perfectly aligned chromophores for second-order nonlinear optics: 4-N,N-Dimethylamino-4′-N′-methyl-stilbazolium 3-carboxy-4-hydroxybenzenesulfonate

A new organic nonlinear optical crystal 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium 3-carboxy-4-hydroxybenzenesulfonate (DSCHS) has been developed with very promising properties for quadratic nonlinear optical applications. DSCHS single crystals with non-centrosymmetric structure have been obtained from aqueous methanol solution. X-ray crystallographic analysis revealed that the crystal structure of DSCHS is triclinic P1 with the chromophores aligned perfectly parallel, leading to the maximum possible order parameter <cos³θ> = 1 in the crystalline state, which is optimal for electro-optics, THz-wave generation and field detection applications. Kurtz powder test has shown that DSCHS exhibits a very large second-order optical nonlinearity, with a 30 percent higher second-harmonic signal than the well-known organic nonlinear optical crystal 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate (DAST).     

The preparation of two-dimensional spindle-type chromophores for second-order nonlinear optical materials

A series of two-dimensional spindle-type chromophores has been synthesized. The detailed synthetic procedure was reported. The factors that influence the nonlinear optical properties such as the donors and acceptor character have been investigated. The chemical structures of the target products have been confirmed by IR, UV-Vis and NMR spectroscopy, elemental and thermal analysis. The spindle-type chromophores have been used to prepare host-guest doped films which exhibited very good thermal and temporal stability. The nonlinear electro-optical coefficients of the host-guest doped films were measured by the Teng-Man technique and gave values in the range from 21 to 29 pm/V.     

立方硅氧烷多枝分子合成与双光子吸收性能研究

以自制立方硅氧烷(OPS)为"核",合成4种立方硅氧烷多枝分子实现了有机/无机分子杂化.在800nm Ti蓝宝石激光器泵浦下开孔z扫描技术测得多枝分子sample 3、4具有明显的双光子吸收,吸收系数分别为1.4×10-11和2.0×10-11 cm/W;CCD光谱仪记录到两样品的上转换荧光峰位在600nm左右.经过立方硅氧烷杂化的多枝分子热分解温度最高可达377℃.