激光大气等离子体光谱特性实验研究

Spectroscopic Study on the Behaviors of the Laser-Induced Air Plasma

报道了对波长为 1.0 6 μm的脉冲激光在气体样品中产生的等离子体进行光谱研究的结果。气体样品为一个标准大气压的纯氮、纯氧和空气 ,光谱探测范围为 30 0～ 90 0nm。结果表明 ,各种气体样品的激光等离子体光谱均表现为连续谱和线状谱的叠加 ,文中分别给出了连续谱和线状谱的基本特征 ,讨论了这些特征与等离子体物理特性的关系 ,并分析了纯氮、纯氧与空气激光等离子体光谱之间的异同。给出了激光等离子体光谱的时间演化和空间分布的基本特征 ,并初步讨论了与这些特征相关的等离子体物理特性。这些结果有助于加深对激光等离子体特性和机理 ,特别是对等离子体产生后的弛豫过程和复合机制的了解。

The results of spectroscopic study on the g as plasma induced by a pulsed laser with wavelength of 1.06 μm are reported. T he gas samples are pure nitrogen, pure oxygen and air, all at the atmospheric pressure, and the spectral range studied is from 300 nm to 900 nm. The results show that the spectra of laser-induced plasmas for the three kinds of gas samples are composed of continuous spectra and line spectra, the basic features of the continuous spectra and line spectra were given, the possible connections of these spectra features to the characteristics of the laser-induced gas plasma were discussed, and the differences of the laser-induced plasmas between pure nitrogen, pure oxygen and air samples were analyzed. The basic features of time evolution and space distribution for laser-induced plasma spectra were also given and the relations between these features and the laser-induced plasma characteristics were briefly discussed. These results are helpful for the better understanding of the laser-induced plasma characteristics, especially those related to the relaxation process and the recombination mechanism of the plasma after its production.