二元激光等离子体的时空演化机制研究  

Research on Space-Time Evolutionary Mechanisms of Species Distribution in Laser Induced Binary Plasma

作　　者：赵洋[1] 张雷[2,3] 程年恺 尹王保 侯佳佳[5] 白成华 ZHAO Yang;ZHANG Lei;CHENG Nian-kai;YIN Wang-bao;HOU Jia-jia;BAI Cheng-hua(School of Semiconductor and Physics,North University of China,Taiyuan 030051,China;Institute of Laser Spectroscopy,State Key Laboratory of Quantum Optics and Quantum Optics Devices,Shanxi University,Taiyuan 030006,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China;China Academy of Ordnance Science,Beijing 100089,China;School of Physics and Optoelectronic Engineering,Xidian University,Xi’an 710071,China)

机构地区：[1]中北大学半导体与物理学院,山西太原030051 [2]山西大学激光光谱研究所,量子光学与光量子器件国家重点实验室,山西太原030006 [3]山西大学,极端光学协同创新中心,山西太原030006 [4]中国兵器科学研究院,北京100089 [5]西安电子科技大学物理与光电工程学院,陕西西安710071

出　　处：《光谱学与光谱分析》2023年第7期2067-2073,共7页Spectroscopy and Spectral Analysis

基　　金：国家重点研发计划项目(2017YFA0304203);长江学者和创新团队发展计划项目(IRT_17R70);国家自然科学基金项目(61975103,61875108,61775125,11434007);国家能源石油炼制技术研发中心(RIPP,SINOPEC);山西省科技重大专项(201804D131036);高等学校学科创新引智计划(111计划)项目(D18001);山西省“1331工程”重点学科建设计划经费(1331KSC);山西省基础研究计划项目(202103021223210,202103021223184)资助。

摘　　要：由于等离子体是激光诱导击穿光谱(LIBS)的光谱源,其内部粒子的分布结构将直接影响LIBS谱线的信噪比,因此研究等离子体粒子分布结构和动态膨胀过程对提高LIBS的定量测量精度具有指导意义。利用时间、空间、波长分辨的双波长差分成像技术分析激光诱导铝锡合金产生的二元等离子体,获取等离子体内各态粒子发射率的时空分布图像,以期探索不同激光支持吸收波(LSAW)类型的等离子体内各态粒子时空分布结构的演化机制。实验通过低、高激光辐照度的脉冲激光,分别构建了激光支持燃烧波(LSCW)和激光支持爆轰波(LSDW)型等离子体。通过观察等离子体的形态、内部结构、粒子分布、粒子寿命,结合元素的物理性质及谱线属性,分析了激光与金属及等离子体之间的相互作用,形成了二元激光等离子体的时空演化机制。结果表明:(1)激光辐照度会改变等离子体的粒子分布结构;(2)低辐照度激光诱导产生的LSCW型等离子体内部有明显的层状分布,激光主要吸收区位于蒸汽等离子体,此时粒子的寿命较短,分布结构主要依赖于元素熔点,低熔点元素会先从难混溶合金表面熔化并析出,分布于蒸汽等离子体顶部;(3)高辐照度激光产生等离子体的传播模型为LSDW型,其内部蒸汽等离子体与冲击气体层有很大的混合区域,激光主要被冲击气体层所吸收,此时粒子寿命延长,分布结构主要依赖于元素的相对原子质量。高激光辐照度会使难混溶合金表面烧蚀区域内的粒子同时汽化,粒子速度与相对原子质量的平方根成反比,即相对原子质量小的粒子飞行速度快,分布在蒸汽等离子体顶部。以上等离子体粒子分布结构的时空演化机制有望普适于其他元素甚至多元等离子体情形。Plasma is the spectral source of laser-induced breakdown spectroscopy(LIBS),and the distribution of its internal species will directly affect the signal-to-noise ratio of the collected emission lines.Therefore,research on the species distribution of vapor plasma is of great importance for improving the quantitative performance of LIBS.In this paper,the laser-induced plasmas on the surface of binary Al-Sn alloy are analyzed using spectrally,spatially and temporally resolved dual-wavelength differential imaging to obtain the emissivity images of species and explore the species distribution and evolutionary mechanism of plasmas with different laser supported absorption wave(LSAW)regime.The laser-supported combustion wave(LSCW)and laser-supported detonation wave(LSDW)dominated plasmas are induced using low and high-irradiance laser pulses,respectively.The interactions between laser,alloy and plasma are analyzed by observing the morphology,species distribution,species lifetime and internal structure of the plasma,and combining with the physical properties of elements and spectral transition structure,the space-time evolutionary mechanisms of the binary laser plasma are formed.From our observation of the emissivity images of species,we can conclude that:(1)laser irradiance can change the species distribution of plasma;(2)the LSCW-dominated plasma has an obvious layer structure,and the absorption zone of laser energy mainly located in vapor plasma.The species’lifetime is relatively short,and the species distribution mainly depends on the melting points of constituted elements in the sample.The element with a lower melting point will melt faster and distribute in the top of vapor plasma;(3)The propagation model of plasma induced by high irradiance laser is LSDW.A large mixing region between the vapor plasma and the shocked gas layer can be observed,and the main absorption zone of laser energy is the shocked gas layer.The lifetime of species in plasma is prolonged,and the species distribution mainly depends on the atomi

关 键 词：激光诱导击穿光谱 激光支持燃烧波 激光支持爆轰波 粒子分布 

分 类 号：O433.5[机械工程—光学工程]