外加电场对激光诱导Al等离子体发射光谱的影响

Effects of additional electric field on the Emission Spectra of Laser-induced Al Plasma

在低压环境下,由Nd:YAG脉冲激光器产生的1.06μm激光烧蚀金属A1靶产生等离子体,观测了外加电场下其空间分辨发射光谱,并由此分析了谱线相对强度、谱线展宽随外加电压的演化特性.结果发现:原子谱线强度及其半高全宽随外加电压的增加均有明显增大,而离子谱线受外加电压的影响较小.从微观机制上分析推断:外加电场使非稳态等离子体中的电子作定向运动,加剧电子与原子之间的碰撞是上述结果的主要原因.此外,由发射光谱线的Stark展宽计算了等离子体电子密度,并由实验结果讨论电子密度随外加电压的演化特性和空间演化特性.

The emission spectrum of A1 plasma produced by ablating A1 target with Q-switch Nd:YAG Laser(wavelength 1.06 μm, pulse width 10 ns) is observed under a low air pressure and direct electricity field. The intensity and the broadness of spectral line in various additional voltages are measured, the result shows that the intensity and the broadness of spectral line of A1 atom are increasing prominently with the additional voltage increasing, but there is little influence on both intensity and broadness of ion spectral line. The collision between atoms and electrons moving in a definite direction with the additional static electric field is considered to be the primary reason for the result mentioned above. In addition, the electron density of plasmas were calculated from measured stark broadening of emission spectral line re- spectively, the effects of the additional voltage on the electron density and the spatial evolution property of the electron density were finally discussed according to the experimental results.