新型高磁光性能铽镓石榴石基磁光晶体的构建及其生长性能研究

Magneto-optical crystal has attracted much attention for numerous applications in in high-end laser processing equipment、high power fiber lasers and optical fiber communication industry，Terbium gallium garnet (Tb3Ga5O12-TGG) crystal has good magneto-optical figure of merit, high thermal conductivity, and high laser-induced damage threshold in the visible-near infrared (VIS–NIR) region. This project will adopts the theoretical approach to get the magneto-optical nature of doped TGG by employing the density functional theory first principles calculations, and focus on the study of the effect of cation doping to the magnetic exchange interactions and crystal field of TGG system, research the microcosmic regulation mechanism of the macroscopic magneto-optical figure of TGG crystal and the emphasis is to improve the process of crystal growth, optimize the concentrations of doped rare earth ions, evaluate the magneto-optical performance and applys it into the high power optical-isolator. As we know, these works has not been reported at home and abroad, and through the research of this project, it will be expected to obtain large-size, high optical quality, high isolation of doped TGG magneto-optical crystal materials with independent intellectual property rights，which is important to promote the development of key materials in high power laser and 5G optical fiber communication system.

磁光晶体在高端激光加工设备、高功率光纤激光器、5G光纤通信产业有重要的应用前景。铽镓石榴石(Tb3Ga5O12;TGG)晶体在可见光到近红外波段具有大的磁光优值、高热导率，和高激光损伤阈值，是较陶瓷、玻璃更优良的磁光材料。本项目拟采用第一性原理计算工具，从理论上深入研究离子掺杂TGG体系的磁光性质，重点从掺杂离子对体系内的磁性离子之间交换作用的影响及其对晶场效应的调整两个角度，阐明晶体宏观磁光特性的微观调控机理，实验中进行晶体制备工艺优化、掺杂离子浓度优化、磁光性能评估、磁光隔离器的应用等方面的系统研究。目前多格位离子掺杂TGG基磁光晶体的研究工作国内外尚未有报道，本项目的实施有望获得具备自主知识产权的大尺寸、高光学质量、高维尔德常数的新型TGG基磁光晶体，对推动国家高功率激光系统和5G光纤通信产业中关键核心材料的发展有重要意义。

本项目围绕研制可见-近红外光谱区内具有高的费尔德常数的磁光晶体材料等方面开展研究，对原有研究计划进行了一定的扩充。按照申请书的研究计划，建立了从微观结构层面探索离子掺杂TGG晶体磁光性能形成机理的理论依据，得到了能够很好解释实验数据的理论模型。在此基础上，通过探索调控工艺参数（如温场设计、生长气氛、退火条件、生长过程中的拉速转速等），制备出了一种大尺寸、高隔离度、高光学质量的TGG基磁光晶体，其晶体的核心指标常数（Verdet旋光常数）在405、533和1064 nm处分别达到583.0、230.1和50.3 rad/(Tm)，比纯TGG材料均有大幅度提高，是目前该波段综合性能较好的磁光晶体。其高的磁光常数和短的紫外截止波长使其有望应用于宽波段磁光器件，对探索新型可见光-中红外磁光晶体材料具有参考价值。