发射光谱法研究纳秒激光烧蚀硅等离子体特性  

Characteristic Study of Plasma Plume Produced by Nanosecond Pulsed Laser Ablation of Silicon Using Optical Emission Spectroscopy

作　　者：高勋[1,2] 金明星[1] 丁大军[1] 林景全[2] 

机构地区：[1]吉林大学原子与分子物理研究所,吉林长春130012 [2]长春理工大学理学院,吉林长春130022

出　　处：《光谱学与光谱分析》2010年第6期1657-1662,共6页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(10534010;10874055;60978014);国家重大基础研究项目资助

摘　　要：利用调QNd3+:YAG激光器三倍频355nm激光脉冲烧蚀空气环境的硅样品,观测不同脉冲激光能量下产生的等离子体在380～420nm范围内的时间-空间分辨等离子体发射光谱,观测到在等离子体羽膨胀初期存在N+发射光谱。在局域热力学平衡近似条件下,根据时间-空间分辨等离子体发射光谱计算得到等离子羽体电子温度和电子密度随时间延时存在二次指数衰减变化,等离子体羽体电子温度和电子密度的空间分布近似呈Lorentz分布,发现在确定激光脉冲能量下电子密度空间分布最大值偏离光谱强度最大空间位置并对产生原因进行分析,探讨了等离子体羽参数与激光脉冲能量的关系。The 355 nm laser pulse from THG （Third Harmonic Generation） of a Q-switched Nd^3＋：YAG laser was used to ablate silicon mounted in air.The time-and space-resolved optical emission spectra were measured for different pulse energy in the wavelength range of 380-420 nm,the emission spectra of N＋ was found for impact ionization of air near target surface on the early stage of plasma plume expansion.Under the model of local thermodynamic equilibrium,the electronic temperature of plasma was deduced to be in the range of 18 000-40 000 K using the Saha equation by the relative line intensities,and the electron density was deduced to be in the 10^17 cm＆-3 scale by FWHM （the full width at half maximum） of Si spectral lines,the temporal and spatial evolution of the electronic temperature and electron density was given,showing that the electronic temperature and electron density exhibited second order exponential decreasing with laser delay time and a Lorentz distribution in space.The reason for the spatial position deviation of the maximum electron density from the maximum spectral intensity was analyzed.The relationship between the plasma plume parameters and laser pulse energy was discussed.

关 键 词：脉冲激光烧蚀 等离子体发射光谱 电子温度 电子密度 

分 类 号：O433.4[机械工程—光学工程]