近年来有机非线性光学及其材料的研究受到极大关注。其中具有代表性的是带有非线性基团的硝基苯胺衍生物,它们的分子不具有对称中心,含有TT共轭电子体系並具有分子内发生电荷转移的特性,从而具备了获取最大二次非线性光学特性的必要条件。此外,4-硝基-4-十八烷基氨基偶氮苯也是一类具有较大非线性光学效应的分子晶体,它具有偶氮基连接起来的共轭体系,其两端分别接有电子给体和受体,因此具有很大的微观二次超极化率β值。但此类化合物的晶体往往具有反演中心,使得宏观非线性二次超极化率x~(2)=0。若采用LB膜 In recent years, the research of organic nonlinear optics and its materials has drawn great attention. Representative of these are nitroaniline derivatives with non-linear groups, their molecules do not have a symmetric center, contain TT conjugated electron system and have intramolecular charge transfer characteristics, so as to obtain the maximum secondary Non-linear optical characteristics of the necessary conditions. In addition, 4-nitro-4-octadecyl aminoazobenzene is also a kind of molecular crystal with large nonlinear optical effect. It has a conjugated system of azo groups, which are connected with electrons Donor and acceptor, and therefore have a large microscopic secondary hyperpolarizability β. However, the crystals of these compounds often have inversion centers, making the macroscopic nonlinear hyperpolarizability rate x ~ (2) = 0. If using LB film