为了分析和检测天然玉石表面元素分布情况, 采用再加热正交双脉冲激光诱导击穿光谱技术对天然玉石表面进行二维元素成像分析.实验研究了正交双脉冲激光诱导击穿光谱条件下脉冲间隔和激光能量对原子辐射强度和信背比的影响.在优化的实验条件下, 对天然玉石样品表面36 mm×10 mm范围内进行了二维扫描分析, 获得了烧蚀坑洞直径约为30 μm的玉石样品表面微量元素Fe的二维分布图.结果表明: 再加热正交双脉冲技术能有效地检测天然玉石样品中的微量元素, 并在相同的样品损伤条件下提高了检测灵敏度.该技术不仅可以实现玉石样品的表面元素分布分析, 为玉石鉴定提供参考, 还可以应用于其他固体样品二维元素分布扫描成像分析, 具有较好的应用价值.

In order to analyze and detect the elemental distribution of natural jade sample surface, reheating orthogonal dual-pulse laser-induced breakdown spectroscopy was adopted to obtain two-dimensional (2D) surface elemental mapping of jade sample. The influence of time interval between two pulses to the signal intensities and signal to background ratio was studied experimentally. Variation relationship between spectral intensity and pulse energy of the reheating laser was discussed. Under optimized experimental condition, the surface scanning analysis of the natural jade within the scope of 36 mm×10 mm was implemented. With the lateral resolution of 30 microns, 2D distribution mapping of trace element iron was obtained. It was demonstrated that reheating orthogonal dual-pulse laser-induced breakdown spectroscopy technique was able to be applied to realize the detection of trace element in natural jade and improve detection sensibility which was helpful for jade identification. This surface elemental mapping technique could be used to achieve the analysis of component distribution of jade and other solid samples which will have nice application prospects.