Abstract：In recent years, the technology of laser induced breakdown spectroscopy has been developed rapidly. As one kind of new material composition detection technology, laser induced breakdown spectroscopy can simultaneously detect multi elements fast and simply without any complex sample preparation and realize field, in-situ material composition detection of the sample to be tested. This kind of technology is very promising in many fields. It is very important to separate, fit and extract spectral feature lines in laser induced breakdown spectroscopy, which is the cornerstone of spectral feature recognition and subsequent elements concentrations inversion research. In order to realize effective separation, fitting and extraction of spectral feature lines in laser induced breakdown spectroscopy, the original parameters for spectral lines fitting before iteration were analyzed and determined. The spectral feature line of chromium (CrⅠ: 427.480 nm) in fly ash gathered from a coal-fired power station, which was overlapped with another line(FeⅠ: 427.176 nm), was separated from the other one and extracted by using damped least squares method. Based on Gauss-Newton iteration, damped least squares method adds damping factor to step and adjust step length dynamically according to the feedback information after each iteration, in order to prevent the iteration from diverging and make sure that the iteration could converge fast. Damped least squares method helps to obtain better results of separating, fitting and extracting spectral feature lines and give more accurate intensity values of these spectral feature lines. The spectral feature lines of chromium in samples which contain different concentrations of chromium were separated and extracted. And then, the intensity values of corresponding spectral lines were given by using damped least squares method and least squares method separately. The calibration curves were plotted, which showed the relationship between spectral line intensity values and chromium concentrations in different samples. And then their respective linear correlations were compared. The experimental results showed that the linear correlation of the intensity values of spectral feature lines and the concentrations of chromium in different samples, which was obtained by damped least squares method, was better than that one obtained by least squares method. And therefore, damped least squares method was stable, reliable and suitable for separating, fitting and extracting spectral feature lines in laser induced breakdown spectroscopy.
Key words：LIBS;DLS;Characteristic spectral lines separation and extraction
王 寅，赵南京*，刘文清，余 洋，方 丽，孟德硕，胡 丽，张大海，马明俊，肖 雪，王 煜，刘建国 . 阻尼最小二乘法用于激光诱导击穿光谱重叠特征谱线分离提取 [J]. 光谱学与光谱分析, 2015, 35(02): 309-314.
WANG Yin, ZHAO Nan-jing*, LIU Wen-qing, YU Yang, FANG Li, MENG De-shuo, HU Li, ZHANG Da-hai, MA Ming-jun, XIAO Xue, WANG Yu, LIU Jian-guo. The Research on Separating and Extracting Overlapping Spectral Feature Lines in LIBS Using Damped Least Squares Method . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2015, 35(02): 309-314.
[1] Celio Pasquini, Juliana Cortez, Lucas M C Silva，et al. J. Braz. Chem. Soc., 2007, 18(3): 463. [2] Kyuseok Song, Yong-Ill Lee, Joseph Sneddon. Applied Spectroscopy Reviewers, 2002, 37(1): 89. [3] Rawat M, Moturi M C Z, Subramaninan V. J. Envoron. Monit., 2003, 5(6): 906. [4] Rios-Arana J V, Walsh E J, Gardea-Torresdey J L. Environment International, 2004, 29(7): 957. [5] Kanga S, Sun X, Ju X, et al. Nucl. Instrum. Methods in Phys. Res. B, 2002, 192(4): 365. [6] David A Cremers，Rosemarie C Chinni. Applied Spectroscopy Reviews, 2009, 44: 457. [7] Baudelet M, Yu J, Bossu M, et al. Appl. Phys. Lett., 2006, 89(16): 163903. [8] Mohamed W T Y. Opt. Laser Technol., 2007, 40(1): 30. [9] David A, Cremers Leon J Radziemski. Hand Book of Laser-Induced Breakdown Spectroscopy. Cambridge University, 2006. 25. [10] Writing Group of Emission Spectral Analysis(发射光谱分析编写组). Emission Spectral Analysis(发射光谱分析). Beijing: Metallurgical Industry Press(北京：冶金工业出版社), 1977. 22. [11] LI Yao-qing(李耀清). Data Process of Experiment(实验的数据处理). Hefei: Press of University of Science and Technology of China(合肥：中国科技出版社), 2003. 114. [12] ZHANG Hua-ren, LI Wei-guo(张华仁，李维国). Journal on Numerical Methods and Computer Application(数值计算与计算机应用), 2010, 30(3): 187. [13] WANG Jia-sheng, QIAO Dong-po, LU Yun-zhang et al(汪家升，乔东坡，路运章，等). Chinese J. Lasers(中国激光), 2010, 37(1): 225.
