半花菁LB多层膜的光学非线性性质研究

Studies on the Nonlinear Optics of Hemicyanine Langmuir-Blodgett Multilayers

利用紫外-可见及收谱和旋转光学二次谐波产生方法研究了光学活性分子半花菁和光学非活性分子花生酸交替Y型多层LB膜中活性分子由于拉膜和“基板”增强的分子取向,我们首次发现并说明了由于平面内附加的极化导致二次谐波强度随LB层数大于平方增长关系.

Substantial in-plane optical anisotropy in Y-type Langmuir-Blodgett multilayers of a hemicyanine dye interleaved with inert material arachidic acid due to dipping-induced and' substrate'-enhanced molecular orientation was demonstrated by polarized UV-visible absorption and rotation-angle second harmonic generation techniques. We gave the first direct evidence for a super-quadratic enhancement of the second harmonic intensity with increasing film thickness due to the additional in-plane polarization.