在空气环境下， 激光诱导等离子体光谱用于激光清洗状态的在线分析快速而准确。 该文利用中阶梯光栅光谱仪探测脉冲激光器作用于干净及表面污染的铜币样品产生的等离子体光谱谱线， 这些谱线中不但包含了清晰的铜原子发射谱线， 还包含空气中氧气和氮气与激光作用产生分解效应的原子谱线。 为了消除单次测量的不确定性， 分析了多次测量的分布恒定的氧原子和氮原子谱线的统计规律， 表明强度分布规律一致， 且相对标准差基本相同， 可以采用单次测量的光谱图变化表示清洗过程中状态。 表面污染的铜币光谱图中包含多元素原子谱线和连续谱线， 清洗干净铜币的光谱图连续谱线消失且只有铜元素谱线， 观察谱线变化就可以表明样品是否被清洗干净。

It is quick and accurate to on-line monitor the sample condition of laser cleaning by means of laser-induced plasma spectrum in air. In the present article, the echelle grating spectrometer was used to detect the plasma spectral lines induced by pulsed laser interaction with copper coin samples with or without contamination. The spectrogram showed that there were clear CuⅠ spectrum lines and air atom spectrum lines of NⅠand OⅠ. In order to eliminate the uncertainty of single measurement, the statistical regularity of NⅠand OⅠspectrum lines was analyzed. Their intensity distribution laws were consistent and their relative standard deviations were the same basically. So a single measurement spectrum could be used to monitor cleaning process. The spectra of copper samples with contamination consisted of many elements atomic spectral lines and continuous spectral lines. But there are CuⅠ spectral lines in the spectra of clean copper samples. As a result, the authors could detect the change of spectral lines to judge whether the laser cleaning samples were clean.