二维聚合物分散液晶光子晶体的制备与研究

为了改善现有聚合物分散液晶(PDLC)光子晶体(PC)的制备方法和电光特性,利用532nm激光干涉条纹引发聚合物和液晶的混合物相分离,采用全息两次不等时曝光的方法,即第1次曝光完成后,将样品沿基板中心法线旋转60°进行第2次曝光,制备得到电可调谐的二维三角格子的PDLC-PC。实验结果表明,两次曝光的时间对聚合物和液晶的相分离程度影响很大,用偏光显微镜观察优化条件下制备得的二维PDLC-PC发现,聚合物和液晶在二维空间上呈规则的三角格子周期性分布。用波长为633nm的He-Ne激光器探测得到在未施加电压时不同晶格常数的PDLC-PC的衍射图样,并根据一级衍射的电光变化曲线,可以看到,其衍射效率可以利用电场进行有效的调节。

Preparation of photonic crystal of two-dimensional polymer dispersed liquid crystal

Electrically controlled two-dimensional-triangular lattice polymer dis persed liquid crystal (PDLC) photonic crystals are fabricated and studied in this paper.In order to im prove the existing fabrication method and electrical controlled characteristics of PDLC photonic crystals,the phase se paration between polymer and liquid crystal is induced by the 532nm laser beam interfere nce pattern.The twice holographic exposures with different time are utilized in this paper,wh ich means that after the first exposure,the sample is rotated about 60° along the central normal line of the sample base plate,and then is exposed again.The experimental results demonstrate that the time of twice expo sures has great influence on the phase separation between polymer and liquid crystal.In addition,the two dimens ional photonic crystal,which is fabricated with the optimized condition,shows regular triangular lattice periodi c ity distribution with a polarizing microscope.The diffraction patte rns of the PDLC photonic crystals with different lattice constants are detected by the 633nm He-Ne laser,when the pho tonic crystals are not under external electric field.The electro-optical charac teristics of the first-order diffraction show that the diffraction efficiency of PDLC photonic crystal can be e ffectively adjusted through external electric field.