新型红外非线性光学晶体CsGeBr_3的研究

Studies on a New Infrared Nonlinear Optical Crystal CsGeBr_3

文中采用理论与实验相结合的研究思路，使用基于量子力学第一性原理的CASTEP程序包，计算了CsGeBr，的能带结构、声子态密度，得到其透过波段是0．52-45μm；采用改进方法合成出CsGeBr3，进行了X射线衍射物相鉴定、红外光谱等测试。结果表明：CsGeBr，的透光范围在红外波段，到25μm仍有80％以上的高透过率，优于CsGeCl3。同时进行了热分析测试、显微结晶的研究以及溶解度曲线的绘制，为下一步进行CsGeBr，的单晶生长做出了准备。并预测CsGeBr3是在红外非线性光学领域有潜力的新型晶体材料。

Adopting a method of combining both theory and experiment, we use CASTEP-based on the Density Functional Theory of First Principle in Quantum Mechanics, to calculate some properties of CsC, eBr3 such as band structure and density of phono states and conclude its theoretical transmittance, from 0.52tzm to 45 tzm; CsC, eBr3 is synthesized by an improved method and characterized by powder X-ray diffraction, infrared spectrum. Results show that in infra- red wave range, up to 25μm,CsGeBr3 possesses a high transmittance, more than 80% ,which is better than those of CsGeC]3. Thermal analysis and research in its microscopic crystal will do help in the later single crystal growth. CsGeBr3 is a potential crystal material in the field of infrared nonlinear optics.