The impact of altering laser focusing conditions on laser-induced breakdown spectroscopy experiments is investigated under ambient Earth laboratory and simulated Martian atmospheres. Experiments were performed in which the focal spot size was varied on a sample by altering the lens to sample distance with respect to targets of interest. Samples investigated include aluminum, copper, and steel. Specific neutral and ionic transitions of each sample were monitored. Atomic and ionic emissions show different intensity peak distributions along the varying lens to sample distance. Ionic species have peak emissions when laser plasma is initiated with a focused spot within the sample in ambient Earth laboratory air, while atomic emissions have peak intensities several millimeters deeper into a sample. In simulated Martian atmospheres, atomic emissions are observed to peak when the laser is focused within the sample, while ionic emissions have peak intensities when the laser is focused near the surface of a sample.

中文翻译：

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激光光束聚焦特性对激光诱导击穿光谱的影响

在环境地球实验室和模拟火星大气下研究了改变激光聚焦条件对激光诱导击穿光谱实验的影响。进行了实验，其中通过改变透镜到样品距离相对于感兴趣的目标来改变样品上的焦斑尺寸。研究的样品包括铝、铜和钢。监测每个样品的特定中性和离子跃迁。原子和离子发射沿不同的透镜到样品距离显示不同的强度峰值分布。当激光等离子体在地球实验室环境空气中的样品内以聚焦点启动时，离子种类具有峰值发射，而原子发射在样品中几毫米深处具有峰值强度。在模拟的火星大气中，