摘要
激光波长和激光入射角是影响激光诱导等离子体空间分布和光谱强度空间分布特性的重要因素。基于流体动力学和SAHA方程,仿真了激光诱导等离子体的二维空间演化过程,研究了激发等离子体的辐射光谱空间分布特性及激光波长、入射角度等参数对等离子体特征谱线空间分布特性的影响。研究结果表明:波长为1064 nm的激光在不同延时条件下,最佳激光入射角度均为0°。当入射角度为0°时,所激发的等离子体辐射在不同的探测角度处均有较强的光谱信号,且在100,500,1000 ns延时条件下,最佳探测角分别为±41°、±11°和±12°。对于不同的波长,当延时分别为100 ns和500 ns且激光以0°入射时,长波长激光所激发的等离子体光谱在不同探测角处的强度均强于短波长激光。当延时为100 ns时,1064 nm波长激光所激发的光谱在最佳探测角位置的强度约为532 nm和266 nm波长激光所激发的光谱在各自最佳探测角位置强度的2倍。随着探测角绝对值的减小,等离子体辐射光谱强度先增大,到达最佳探测角后强度再减小。入射波长分别为532 nm和1064 nm的激光诱导击穿光谱实验结果验证了仿真结果。
Laser wavelength and incident angle are important factors that influence the spatial distribution and spectral intensity of laser-induced plasma.Based on the fluid dynamics and SAHA equation,this paper simulates the two-dimensional spatial distribution of laser-induced plasma,calculates the spatial distribution of radiation spectrum of the excited plasma,and studies the influences of laser incident angle,wavelength and other parameters on the spatial distribution characteristics of plasma characteristic spectral lines.The research results show that that 0°is the best incident angle for 1064 nm laser with different delay conditions.When the incident angle is 0°,the excited plasma radiation has stronger spectral signals at different detection angles.Moreover,the optimal detection angles are±41°,±11°and±12°at 100 ns,500 ns and 1000 ns delay conditions,respectively.For different wavelengths,when the delay time is 100 ns or 500 ns and the laser is incident at 0°,the intensity of plasma spectrum excited by 1064 nm laser at each detection angle is stronger compared that by a short wavelength laser.When the time delay is 100 ns,the intensity of the plasma spectrum excited by the 1064 nm laser at the optimal detection angle is approximately twice that by 532 nm or 266 nm laser at each optimal detection angle.With the decrease of the absolute value of the detection angle,the spectral intensity of the plasma radiation first increases and then decreases at the optimal detection angle.The simulation results are verified by the laser induced breakdown spectroscopy experimental results with incident wavelengths of 532 nm and 1064 nm,respectively.
作者
孙晨薇
步扬
王远航
吴芳
蔡亚超
王向朝
Sun Chenwei;Bu Yang;Wang Yuanhang;Wu Fang;Cai Yachao;Wang Xiangzhao(Laboratory of Information Optics and Opto-Electronic Technology,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;Department of Physics,Shanghai University,Shanghai 200444,China)
出处
《光学学报》
EI
CAS
CSCD
北大核心
2021年第21期222-234,共13页
Acta Optica Sinica
基金
上海市科委项目(18511104500)。
关键词
光谱学
激光诱导击穿光谱
等离子体
特征谱线
空间分布
最佳探测角
最佳入射角
spectroscopy
laser-induced breakdown spectroscopy
plasma
characteristic spectral line
spatial distribution
optimal detection angle
optimal incidence angle
