【作者】 董鹏； 李群艳； 郭省才； 程丙英； 倪培根； 张道中；

【Author】 DONG Peng, LI Qun-yan, GUOXing-cai, CHENG Bing-ying, NI Pei-gen, ZHANG Dao-zhong(1. State Key Laboratory of Heavy Oil Processing, University of Petroleum, Beijing J 02200, China; 2. Optical Physics Laboratory, Institute of Physics, Chinese Academy of Science, Beijing 100080, China)

【机构】 石油大学重质油加工国家重点实验室； 中国科学院物理研究所光开放实验室；

【摘要】 光子晶体是指具有光子带隙结构的一类新材料。它可有效地控制光子的传播,因此是全光集成回路器件的基础。探索构成三维光子晶体的途径之一是组装具有光波长量级的单分散胶体微球。本文着重介绍了用300nm单分散二氧化硅胶体微球在重力场下自组装成胶体晶体的步骤,特别是提出了一种颗粒分选技术可以在很大程度上排除粘结颗粒对组装的不良影响。该技术的原理是基于单个微球与粘结球在液体中的重力沉降速度不同,利用颗粒模型测定了单个微球与最慢粘结球的相对速度,据此将不含粘结球的单球分选出来,再进行晶体组装,扫描电镜和透射光谱的表征结果显示,颗粒分选技术有效地提高了晶体组装质量。更多还原

【Abstract】 Photonic crystals are the novel materials with photonic bandgaps (PBG) which are capable of controlling the propagation of photons in much the same way as a semiconductor does for electrons. It is the bases of designing all-optical, integrated circuits. One of the investigated contracting ways for the fabrication of three dimensional photonic crystals is assembling the monodisperse colloidal spheres with the diameter comparable light wavelength into periodic lattices. The self-assembly procedure in a gravitational field with 300 nm monodisperse colloidal silica spheres was demonstrated. In order to separate the aggregated spheres in the form of doublets, triplets, etc. from single spheres, a technique for the strict selection of silica spheres was developed. The selection is based on different settle velocities of single spheres and aggregated spheres in a suspension. From a series of model experiments and calculation, it was determined when and where the only single spheres can be taken out of the suspension during a sedimentation period. The scanning electron microscopy (SEM) images and the optical transmission spectra of the colloidal crystals showed that the technique for selection of silica spheres is effective on the improvement of crystal quality.更多还原