报告题目：About some nonlinear optics effects which may influence essentially on SLM of powder substance
报告人：Trofimov（莫斯科国立大学教授）
报告时间：2018年11月07日星期三上午09:30
报告地点：机械与汽车工程学院19号楼209会议室
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机械与汽车工程学院
2018年11月5日
报告人简介：
Trofimov教授目前任职于俄罗斯罗蒙诺索夫莫斯科国立大学，是俄罗斯教育部荣誉职员,俄罗斯科学基金会理事会成员, 俄罗斯基础研究基金特聘专家, 国际会议计划委员会成员，俄罗斯前5%的科学家, 588篇科学杂志发表物，344篇摘要及报告一半以上发表在影响因子大于2.5的杂志上，在俄罗斯本国的学术数据库的被引次数高达6400，超过俄罗斯95%的科学家。1987年获得列宁科姆莫尔奖,1992年获得索罗斯科学家奖, 两次俄罗斯院士提名奖。主要研究领域包括激光增材制造，脉冲激光与物质相互作用，使用宽带太赫兹脉冲对物质进行检测和识别，开发相关算法用于增加THz无源摄像机所捕获的图像质量等相关研究。
报告摘要：
Selective laser melting occurs at high intensity of the laser beam. This beam is scanning when the melting of metal powder. The powder is placed in a box with gas (for example, Ag). This gas continuously moves across the laser beam. Therefore, at list two nonlinear effects appear when process of melting takes place: violation of Snell’s law for reflection of powerful laser beam and thermal blooming of CW in moving gas. In report these physical effects are illustrated and discussed their possible influence on melting of metal powder and quality of solidification of liquid metal.
Certain attention is paid to laser beam propagation in (reflection from) ordered and disordered structure. The main feature of such structure is appearance of transparent and forbidden zone reflection coefficient in dependence of laser beam frequency. It may be important because the powder may be considered as ordered structure and there is a dependence of absorption coefficient from diameter of powder particles.A possibility of realization of the bistable process of metal heating is discussed also.
