超短脉冲激光诱导信息材料非平衡晶化动力学研究

项目名称： 超短脉冲激光诱导信息材料非平衡晶化动力学研究

项目编号： No.51471009

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 刘富荣

作者单位： 北京工业大学

项目金额： 85万元

中文摘要： 光致相变技术是利用激光诱导物质相在晶态/非晶态之间可逆转变来实现信息快速存储的一项技术，如何阐明激光诱导超快晶化机理是当前本领域尚未解决而又亟待解决的一个根本问题。不同于纳秒短脉冲激光诱导晶化，超短脉冲激光诱导晶化同时受热和非热因素驱动，解释这两种因素的作用机制成为其晶化动力学研究的关键。本项目首先基于实验研究超短脉冲激光诱导晶化后组织、结构和性能分布特征，并采用泵浦-探测研究超短脉冲激光辐照信息材料时的非线性吸收、电子激发及晶化等动力学过程；接着，建立考虑电子激发效应的双温模型，阐明超短脉冲激光辐照信息材料的热量输运规律，并建立激光作用耦合的第一原理分子动力学模型，阐述激光诱导晶化微结构及性能的起源和演化规律；最后，在实验和模拟研究基础上，揭示超短脉冲激光诱导非平衡晶化动力学机制，发展超短脉冲激光诱导晶化动力学理论。项目的开展，不仅具有重要的理论意义，也具有深远的工程应用背景。

中文关键词： 相变材料；晶化动力学；第一原理分子动力学；超短脉冲激光

英文摘要： Laser induced phase transition is a technology to achieve the information storing by the ultrafast transition between the crystalline and amorphous states of the phase change materials (PCMs). How to explain the mechanism of the ultrafast crystalization has become one of the key problems to be settled in this field. Different from the crystallization induced by a nanosecond pulsed laser, the crystallization induced by an ultrashort picosecond or femtosecond pulsed laser is regarded by a process trigered by both the thermal and non-thermal factors, therefore, how to explain the effects by these two factors becomes a key to study the crystallization dynamics.In the present study, the distribution characteristics of the microsture and properties after the ultrashort pulsed laser irradiation are first studied experimentally, and based on the pump-probe technology, the dynamics processes including the nonlinear absorption, electronic exitation and crystallization are further investigated. Subsequently, an electronic exitation process integrated Two-Temperature model is proposed to investigate the transportation of heat flow within the PCMs, furthermore, a coupled ab initio molecular dynamics model is also developed to explore the origin of the structure and properties affected by the ultrashort pusled laser irradiation. Finally, based on the experimental and numerical investigations, the mechanism of the ultrafast crystallization is uncovered and the theory of the crystallization dynamics induced by an ultrashort pulsed laser is established. The work based on the project is very important not only for the development of the basic theory of the ultrafast transformation but also for engineering applications.

英文关键词： Phase change materials (PCM);Crystallization dynamics;Ab initio molecular dynamics(AIMD);Ulatrashort pulsed laser