共轴变焦激光诱导击穿光谱定量分析  

Quantitative analysis of coaxial zoom laser-induced breakdown spectroscopy

作　　者：李欣 吕正一 崔博伦 张家铭 刘紫莹 黄荀 赵天卓 Li Xin;Lv Zhengyi;Cui Bolun;Zhang Jiaming;Liu Ziying;Huang Xun;Zhao Tianzhuo(Beijing Institute of Space Mechanics and Electricity,Beijing 100094,China;Beijing Aviation Intelligent Remote Sensing Equipment Engineering Technology Research Center,Beijing 100094,China;Aerospace Dongfanghong Satellite Co.Ltd.,Beijing 100094,China;University of Chinese Academy of Sciences,Beijing 100049,China;Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100094,China)

机构地区：[1]北京空间机电研究所,北京100094 [2]北京市航空智能遥感装备工程技术研究中心,北京100094 [3]航天东方红卫星有限公司,北京100094 [4]中国科学院大学,北京100049 [5]中国科学院空天信息创新研究院,北京100094

出　　处：《红外与激光工程》2023年第12期91-102,共12页Infrared and Laser Engineering

基　　金：国家重点研发计划项目(2022YFF1300202)。

摘　　要：在诸如火星探测等极端环境原位检测应用中,共轴变焦距激光诱导击穿光谱技术发挥了重要作用。为了充分发挥变焦系统的应用效能,距离校正必不可少。现有距离校正方法多为针对单一场景的经验算法,适用范围有限。因此,提出一种基于等离子体物理的参考脉冲诊断法,无需标定设备响应即可诊断等离子体温度,进而实现变焦距定量分析。对比了所提出算法与Saha-Boltzmann法的诊断结果,最大相对误差小于8%。采用13块铝基标准样品进行了变焦距定量实验,9块于2 m处建立定量模型,4块分别于1.5、2、2.4、2.7、3 m处进行检测。反演结果中含量超过1%的元素,11号样品中Si的相对误差最大,为16%,其余大部分小于8%;含量低于1%的元素,大部分相对误差在10%~30%之间,验证了所提出的方法能够实现变焦距激光诱导击穿光谱定量分析。Objective In in-situ analysis applications,where the promise of laser-induced breakdown spectroscopy(LIBS)is significant,the use of fixed analysis distances often proves impractical.Zoom-LIBS,with its greater flexibility,emerges as a more viable solution.The typical structure of a zoom-LIBS system employs a coaxial light path for both excitation and collection.This design enables precise laser focusing on the object's surface at various distances by adjusting the focal length of the telescope.However,the adjustment in focal length induces changes in the plasma state and system efficiency.Consequently,the LIBS equipment collects plasma spectra with varying intensities and characteristics.Integrating these spectra directly into a quantitave model for accurate inversion results becomes challenging.Moreover,standardizing plasma spectra after accurately calibrating equipment parameters at all analysis distances is a complex task,especially considering the diverse application scenarios of zoom-LIBS equiptment.To address these challenges,this paper proposes a reference pulse diagnostic method.This innovative approach allows the diagnosis of plasma temperature without the need for calibration equipment.Subsequently,the plasma spectra collected at different analysis distances can be corrected,facilitating accurate zoom-LIBS quantitative analysis.Methods The reference pulse diagnostic method consists of three key steps.Firstly,two lasers with power densities P1 and P2 are used for plasma excitations,where one serves as an analysis pulse and the other as a reference pulse.Following the principles of plasma radiation theory,the ratio of the intensity of atomic lines at the same wavelength in the two acquired spectra is computed.This ratio,denoted as V1,is a function of the plasma temperature.In the seconde step,the ratio of the intensity ratio of the ion line to the atomic line in the spectra generated by both the excitation pulse and the reference pulse is calculated.This ratio,denoted as V2,is also a function of the plasma

关 键 词：激光诱导击穿光谱 变焦距检测 定量分析 参考脉冲诊断法 

分 类 号：O433.4[机械工程—光学工程]