【作者】 杨丽；

【导师】 王清月；

【作者基本信息】 天津大学 ， 光学工程， 2007， 博士

【摘要】 本论文对金属薄膜飞秒激光诱导向前转移(fs-LIFT)规律进行了系统的实验研究。并理论研究了飞秒激光与金属材料作用的规律。论文的主要内容包括:一、采用双温模型对飞秒激光烧蚀金属材料的三维温度场进行了数值模拟。计算了铜、铝两种材料的单脉冲飞秒激光烧蚀能量阈值,电子-晶格能量耦合时间,以及材料开始烧蚀时间随单脉冲飞秒激光能量变化的规律等。并计算得到了铜材料的烧蚀半径、烧蚀深度随单脉冲飞秒激光能量变化的规律。模拟结果表明,随着单脉冲飞秒激光能量的增加,材料烧蚀引起的喷射出现的越早,完成烧蚀所用时间越长。同时,材料烧蚀孔半径、深度增加,最终达到饱和。二、首次系统地实验研究了飞秒激光诱导铜薄膜前向转移,并取得了重要进展。包括:1).铜薄膜fs-LIFT能量阈值实验研究。实验分别获得了厚度为40、80及450nm铜薄膜的fs-LIFT能量阈值。分析认为:在阈值能量时,较薄铜“源”膜的自由表面处于熔融态,而较厚铜“源”膜的自由表面处于固态;材料主要以液态形式转移。2).铜薄膜fs-LIFT沉积点尺寸与激光能量、“源”膜厚度的关系研究。实验结果表明:在阈值能量时,不存在“源”膜厚度越小,沉积点尺寸越小的规律。3).激光能量对fs-LIFT沉积点形貌影响的实验研究。实验结果表明:当激光能量相对较小,刚达到阈值能量附近时,沉积点呈现滴的形貌;随着能量的增加,沉积点呈现出岛状的形貌;对于较高的能量,沉积点呈现出环状形貌。4).接收距离对fs-LIFT沉积点形貌、尺寸影响的实验研究。实验结果表明:在接收距离为几十个微米的范围内,当铜膜厚度相对较薄时,沉积点的直径与接收距离成反比;而当铜膜厚度相对较厚时,沉积点的直径与接收距离成正比。三、实验研究了飞秒激光诱导铝薄膜前向转移的规律,并取得了重要进展。包括:得到了两种不同厚度铝薄膜的fs-LIFT能量阈值,沉积点的尺寸、形貌随激光能量变化的规律等。并实验研究了激光聚焦位置对沉积点形貌、尺寸的影响。四、实验研究了利用fs-LIFT技术制作线阵及微图形时,飞秒激光烧蚀点的点间距,激光能量,以及接收距离等参数的影响,研究制作了各种形状的微图形。更多还原

【Abstract】 In this thesis, experimental studies on the micro-deposition of metal film by femtosecond laser-induced forward transfer (fs-LIFT) are presented. Mechanisms on interaction of femtosecond laser pulses with metal materials are studied. The main contents are classified as follows:1. The ablation processing of metal materials with femtosecond laser pulses were simulated by the 2D Two-Temperature Model. According to the characteristic of femtosecond laser ablation, the threshold fluence for single pulse ablation of copper and aluminium were calculated. And the dependence of the electronic-lattice coupling time on irradiated laser pulse energy was studied on the basis of the simulation of the electronic and lattice’s temperature, which present a steady increase with increasing the pulse fluence. Besides, the ablation depth and the ablation radius of copper for single pulse ablation were calculated. And the dependence of the start ablation (phase explosion arises) time of copper and aluminium on irradiated laser pulse energy was studied. The simulation results indicate that the material jet due to phase explosion is earlier and the duration of ablation lasts is longer with increasing the pulse fluence. And at the same time, the ablation depth and the ablation radius of material were increased until saturation.2. Systemic experimental study on deposition of copper film by femtosecond laser-induced forward transfer had been accomplished for the first time, in which the important headway had been acquired experimentally. Consist: (a). The threshold fluence for transfer researches experimentally. The threshold fluences of copper thin film of 40, 80 and 450 nm in thickness had been ascertained. It is wise up that the material is transferred and deposited on to the acceptor substrate in the form of liquid droplet mainly as the laser fluence was slightly above the threshold fluence. The droplet formation for the thinner film was a result of blow-off of molten film from the quartz substrate by compressive stress of plasma when the free surface was melted. Whereas for the thick film the higher pressure of plasma made the free surface of solid phase burst out, which resulted in the phenomenon that not only the solid material was sputtered but also the morphology of deposited film in the liquid state was made irregular. (b). Influence of the pulse fluence on the size of deposited film. The experimental results show that at threshold fluence, a thinner film generates a larger-sized of ablated and deposited dot. (c). Influence of the pulse fluence on the morphology of deposited film. The three typical morphologies of deposited dots was shown. At single laser pulse fluence slightly above the threshold, the material is transferred and deposited onto the acceptor substrate in the form of liquid droplet. With the increasing of the energy, the morphology of the deposited dots became island-like and circular. Whenas for higher energies, the transferred dots show ring-like morphology. (d). Influence of the accept distance on the size and morphology of deposited film. The experimental results show that the diameters of deposited dots are inversely proportional to the accept distance for the thinner film as the accept distance is within the range of several ten micron. Whereas for the thicker film that are inversely proportional.3. Systemic experimental study on deposition of aluminium film by femtosecond laser-induced forward transfer had been accomplished for the first time, in which the important headway had been acquired experimentally. Consist: The threshold fluences of aluminium film of 150 and 500 nm in thickness had been ascertained. The influence of the pulse fluence on the size and morphology of deposited dots had been researched. And experimental study on the influence of laser focusing location on the size and morphology of deposited dots had been completed.4. Influence of various parameters on the fabrication of line and micro lattice patterns by fs-LIFT had been investigated experimentally, for example: space between dot and dot, laser fluence and the accept distance etc. And the various micro lattice patterns had been fabricated.更多还原