碱土金属卤素硼酸盐紫外倍频晶体的结构设计、水热合成和性质研究

项目名称： 碱土金属卤素硼酸盐紫外倍频晶体的结构设计、水热合成和性质研究

项目编号： No.21301189

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 张方方

作者单位： 中国科学院新疆理化技术研究所

项目金额： 25万元

中文摘要： 紫外倍频晶体是全固态激光器的关键材料，其研制对推动紫外激光技术的应用和发展具有重要意义。设计合成倍频效应大、透光波段宽、物化性能稳定等综合性能优异的紫外倍频晶体仍是一项挑战。本项目拟结合以下三点："硼酸盐结构复杂多样且BO3基团及其组成的硼氧聚阴离子基团具有ＮＬＯ活性；碱土元素无d-d电子跃迁，形成的键离子性强，利于产物的紫外光透过和带隙增大；卤素原子电负性大，能够较大程度影响电子分布，辅助形成不对称中心结构"，在碱土-卤素-硼酸盐体系探索新型紫外倍频晶体。以无心水合碱土金属硼酸盐结构为切入点，利用OH-与卤素离子在半径、价态和成键类型方面的相似性，在结构中引入卤素离子。采用水热法调控碱土和卤素离子来影响晶体组成和结构，进而调控晶体倍频效应，合成倍频效应大、紫外吸收边短的倍频晶体。分析晶体结构和电子结构特征，揭示组成和结构对倍频效应的影响规律，为新型紫外倍频晶体结构设计和可控合成提供指导。

中文关键词： 紫外倍频晶体；碱土金属卤素硼酸盐；合成；结构设计；倍频效应

英文摘要： Studies on the ultraviolet (UV) frequency doubling crystals are of importance because they are the key materials of the all-solid state laser and play crucial roles in the application and development of the UV laser technology. However, it is still a challenge to design and synthesize UV frequency doubling crystals with excellent comprehensive properties such as large second harmonic generation, wide transparency range, stable physical and chemical properties, and so on. This project intends to explore novel UV frequency doubling crystals in tne alkaline-earth halogen borates by considering the following merits. Firstly, the borates possess versatile structures and both of the BO3 groups and the polyanion groups consisting of BO3 groups have nonlinear optical (NLO) activities. Secondly, the chemical bond formed with the alkaline-earth element is ionic and there is no d-d electron transition, which are conducive to obtain crystals with large band gap and UV transparency. Thirdly, halogen atoms are electronegative elements which can greatly influence the electron distribution in the structure and thus help to fabricate acentric structures. Therefore, this project focus on the alkaline-earth halogen borate systems. Because the radius values, valence states and bonding types of OH- and halogen anions are similar,

英文关键词： UV frequency doubling crystal；alkaline-earth halogen borate；synthesis；structural design；frequency doubling efficiency