时间分辨飞秒激光诱导击穿光谱的设计与研究  

Design and Study of Time-Resolved Femtosecond Laser-Induced Breakdown Spectroscopy

作　　者：宁倩倩 杨佳浩 刘晓琳 何玉韩[1] 皇甫至超 余文静 王朝晖[1] NING Qian-qian;YANG Jia-hao;LIU Xiao-lin;HE Yu-han;HUANGFU Zhi-chao;YU Wen-jing;WANG Zhao-hui(State Key Laboratory of Physical Chemistry of Solid Surfaces,Key Laboratory of Spectrochemical Analysis and Instrumentation,Ministry of Education,College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005,China)

机构地区：[1]厦门大学化学化工学院,固体表面物理化学国家重点实验室,谱学分析与仪器教育部重点实验室,福建厦门361005

出　　处：《光谱学与光谱分析》2023年第4期1083-1087,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(22072121);国家自然科学基金创新研究群体科学基金项目(21521004)资助。

摘　　要：激光诱导击穿光谱(LIBS)具有样品无需预处理,操作简单,分析快速等优点,已在多个领域获得应用。实验搭建了飞秒激光诱导击穿光谱(Fs-LIBS)装置,使用波长800 nm,脉宽100 fs的飞秒激光器作为激发光源,门控ICCD作为检测器。LIBS用于检测静态液体时会发生液体波动飞溅等问题,信号较差,该实验以液体射流的方式进样,以NaCl标准溶液为模型体相,Na(Ⅰ)589.0 nm为分析线进行测试。该实验采用时间分辨LIBS的方法,考察了飞秒激光作用于样品后的LIBS发射光谱随时间的演化,发现在激光脉冲作用于样品表面40 ns后Na原子发射谱线达到最强,信背比也同时达到最大值。表明飞秒脉冲激发的LIBS可以通过时间分辨,有效消除宽带背景发射的影响,更高效地对样品中的待测目标进行检测。研究了激光激发功率、ICCD门宽、激光焦点到样品表面距离等实验条件对LIBS信号强度和信噪比的影响,并优化了实验参数。在延迟时间40 ns、激发功率100 mW、门宽5μs、焦点位于样品前表面的最佳实验条件下,测试了海水样品的LIBS光谱和Na含量,检测了不同浓度NaCl标准溶液,并绘制了Na(Ⅰ)589.0 nm的定标曲线,得到NaCl标准溶液中Na元素的检测限为0.98 mg·L^(-1)。实验结果表明,LIBS技术满足快速、实时检测元素的要求,可以用于研究等离子体动力学演化过程,实现元素的定性和定量分析。Laser-induced breakdown spectroscopy(LIBS)has the advantages of no sample pretreatment,simple operation,rapid detection,etc.,and it has been applied in many fields.In this experiment,femtosecond laser-induced breakdown spectroscopy(Fs-LIBS)was developed,using a femtosecond laser with a wavelength of 800nm and a pulse width of 100fs as the excitation light source and a gated ICCD as the detector.When LIBS detects bulk liquids,problems such as liquid fluctuations and splashes will occur,and the signal will be poor.In this experiment,NaCl standard solution jet flow was used to test and optimize the system,and Na(Ⅰ)589.0nm was chosen as the analysis line.The evolution of the LIBS emission spectrum after the femtosecond laser excitation was investigated.The maximum Na atom emission and the best signal-to-background ratio were obtained after 40ns of laser excitation.It shows that femtosecond time-resolved LIBS can effectively eliminate the influence of broadband background emission and more efficiently detect the target.The effects of laser excitation power,ICCD gate width,the distance between the laser focus to sample surface on LIBS intensity and signal-to-noise ratio were studied and optimized.At the best experimental parameters:40ns delay time,100mW excitation power,5sgate width,and laser focus right on the front surface of the sample,the LIBS spectrum and Na content of a seawater sample were tested,and the detection limit of Na for NaCl standard solution was determined to be 0.98mg·L^(-1).The experimental results show that the LIBS technology meets the requirements of rapid and real-time detection of elements,can be used to study the plasma dynamics evolution process and achieve a qualitative and quantitative elements analysis.

关 键 词：飞秒激光诱导击穿光谱 时间分辨 NACL溶液 液体射流 检测限 

分 类 号：O657.3[理学—分析化学]