A PVK—Based High—Performance Photorefractive Polymer Composite Under a Low External Electric Field

We describe a PVK-based photorefractive polymer composite doped with disperse red 1,poly-butylacrylate and TNF.Using the two-beam coupling experiment,we investigate its photorefractive properties as well as the dynamic process of the index gratings in the sample.We observe the photorefractive effect in the absence of an applied external electric field.The two-beam coupling gain coefficient was measured to reach a value as high as 140cm^-1 in the absence of an external applied electric field and a value of 470cm^-1 at a poling dc electric field of 25V/μm.     

掺杂有机给体与受体分子的向列相液晶的光折变研究

制备了一种掺杂有机给体和受体分子的向列相液晶（nematic liquid crystals）材料。参数的给体和受体分子使液晶材料的光折变性能大为提高。用此材料做成的夹心器件进行了能量二波耦合，简单并四波混频等实验。在外加低直流电场（0．5KV/cm)条件下，观察到了光折变增益Γ为441cm^-1，二波能量耦合实验中观察到的衍射光束达到6级，简并四波混频中最大衍射效率达到58％，写入混合材料的信号光栅已可保存数小时而无明显衰减。