时间：2024年10月21日上午10:30
地点：理工楼18号楼-307学术报告厅
主讲：KOKH ALEXANDER，俄罗斯科学院西伯利亚分院地质与矿物学研究所实验室主任
主办：光电与信息工程学院，医学光电科学与技术教育部重点实验室，福建省光子技术重点实验室
专家简介
KOKH ALEXANDER，普罗霍罗夫普通物理研究所，技术科学博士学位，现任俄罗斯科学院西伯利亚分院地质与矿物学研究所实验室主任，主要开展非线性及激光晶体生长方法研究、分析研究新型非线性晶体等方向的研究。主要研究成果为合成并生长了新化合物K7CaR2(BO3)2（其中R=Nd,Y,Yb）晶体，并研究了其结构特征、光谱、发光和热性能。 Kurtz-Perry 方法证实了使用所获得的晶体用于 Nd 激光器二次谐波产生的前景；发现了一类新的具有线性二向色性效应氟硼酸盐，可用作二向色性偏振器等。
讲座简介
When growing crystals by axisymmetric methods, the most common approach is to create maximum symmetrical homogeneous heat fields. The symmetry of such fields can be described by the symmetry of a stationary cone (L∞/∞P). Isotherms in the horizontal sections of those fields are circles. In contrary to this approach, we are developing one, based on the creation of inhomogeneous thermal fields, both static and dynamic. A dynamic inhomogeneous thermal field is used for the growth of nonlinear optical crystal of lithium triborate LiB3O5 (LBO). The growth is performed with the Kyropoulos solution-melt method with low axial temperature gradient and without mechanic rotation of the crystal. To enhance the natural convection processes in the solution-melt, "hot spots" moving around the growth crucible are created by switching on the corresponding heating elements of the growth furnace. Thus such method of influence on the process of crystal growth can be so called the heat field rotation. Acquired experience shows that changing the symmetry of the heat field (creating inhomogeneous heat fields) provides great opportunities for controlling the processes of heat and mass transfer during crystal growth progress. This is especially important when growing borate crystals due to viscous crystallization media. The poster presentation demonstrates some options that effected the growth of LBO crystals.
