大尺寸硒铟锂单晶小角倾斜水平温梯冷凝法制备技术基础研究

LiInSe2 crystal is one of the most important mid-infrared non-linear optical crystal. It has broad application perspective due to its excellent non-linear optical and thermodyanmic properties. However, current research is mainly focused on the theoretical calculations. The key problems, such as the effects of the synthesis method and the process parameters on the crystal performances, have not been reported yet. The applicant proposes to grow LiInSe2 single crystals by the combination of the visual horizontal gradient condensation method and small angle inclined method, and determine the optimal process parameters for the growth of large size crystals with high quality and high performance. Firstly, the micro defects of the crystal were analyzed by the chemical corrosion method combined with the synchrotron radiation and high resolution X-ray diffaction. Then by means of inductively coupled plasma atomic emission spectroscopy, X ray diffraction, Infrared spectoscopy and Raman spectroscopy, we determined the composition, structure and optical properties of the crystal, and analyzed the effects of the growth process on the composition of the crystal.This project will provide a set of method for the preparation of larger size high quality LiInSe2 single crystal and the optimal growth process parameters. In the mean time, the relation among the crystal growth process, the crystal composition , the defect structure and the optical properties will be revealed, and the theoretical evidence for the development of novel middle and far-infrared nonlinear optical crystals will be established, which will have great theoretical and practical significance.

硒铟锂(LiInSe2)晶体是重要的中红外非线性光学晶体,兼具优异的非线性光学和热力学性质,具有广阔的应用前景。但目前研究重点都集中理论计算,对其制备方法和工艺参数对晶体性能的影响等关键问题未见报道。申请人提出采用可视水平梯度冷凝法结合小角度倾斜方法生长LiInSe2晶体,确定生长出高质量、高性能的大尺寸晶体的最佳工艺参数。首先,采用化学腐蚀法,结合同步辐射和高分辨X射线研究晶体的微观缺陷。然后,通过电感耦合等离子体发射谱、X射线衍射光谱、红外透射光谱、拉曼光谱等手段研究晶体的成分、结构和光学性能,分析生长工艺对晶体成分的影响规律。本项目将给出一套制备大尺寸、高质量LiInSe2单晶的方法和最优工艺参数,同时,揭示"晶体生长工艺-晶体成分-缺陷结构-光学性能"的关系,为开发新型中远红外非线性光学晶体提供理论依据,具有较大的理论与实际意义。

中红外非线性光学晶体在国防和民用领域上有重要应用前景，如红外对抗、激光制导和环境监测等。硒铟锂(LiInSe2) 晶体兼具有较大的非线性光学系数、较宽的透过波段、高的热导率、宽的带隙等特性，是一综合性能优异的新型中红外波段非线性光学材料。本项目采用可视水平梯度冷凝法结合小角度倾斜的方法成功制备了大尺寸、高质量LiInSe2单晶。研究高纯度单相的LiInSe2多晶料合成工艺，通过反应热力学与动力学原理进行分析与实验，确定出最优合成工艺参数；研究高质量LiInSe2单晶生长工艺，根据生长基元、结晶界面特性，分析晶体生长习性与规律，设计出合理温场，确定优良晶体生长工艺；研究多晶合成、生长工艺、缺陷结构和光学性能的关系，通过改进生长工艺减少缺陷，提高晶体性能，生长出性能优异中红外波段非线性光学LiInSe2晶体材料(尺寸为6mm*30mm) 。