4-硝基-4′-氨基偶氮苯的光学性质研究

采用紫外可见吸收和二次谐波产生技术研究了“推-拉”型偶氮苯分子Langmuir-Blodgett(LB)膜的光谱和二阶非线性光学特性.4-硝基-4′-氨基偶氮苯(NAA)分子能制成很好的LB多层膜,在稀溶液中以单体的反式异构体形式存在,在膜中主要以J-聚集体的形式存在,LB膜的紫外可见吸收谱的吸收峰较之溶液的发生了52 nm的红移.NAALB膜的二阶非线性极化率χ(2)为19.59×10－8 esu,一阶超极化率β值较大,约为1.974×10－29 esu.其光学二阶非线性起源于电偶极子机制.

Investigation on Optical Properties of 4-(nitro)-4'-(amido) Azobenzene

The spectra and nonlinear optics properties of a push-pull azobenzene compound were investigated by using UV-visible absorption spectra and second harmonic generation (SHG) technique in Langmuir-Blodgett films. The high-quality LB multilayer films had been deposited by the 4-(nitro)-4′-(amido)-azobenzene. The monomers are the main formation for the the 4-(nitro)-4′-(amido)-azobenzene in dilute solution, but the J-aggregation are the main formation in the LB films. The peak position of UV-visible absorption spectra in LB films exhibited a distinct red shift about 52 nm relative to that of this compound in the chloroform solution. The second order nonlinear optical susceptibility of LB films χ(2) was about 19.59×10－8 esu. The molecule has a significant second-order nonlinear hyperpolarizability. The hyperpolarizability β was about 1.974×10－29 esu.The origin of SHG was the electric dipole mechanism for this molecule.