Spatial resolution in conventional LIBS imaging is usually limited by the fact that for a given laser-detector combination sufficient sensitivity can only be achieved with a large enough laser spot size. Below a certain threshold for the spot size (depending on sample, analyte, and concentration), the signal-to-background ratio will not allow a discrimination between sample areas of low and high concentration.

The conventional approach is to place laser shots in such a way that they do not overlap on the sample surface. However, we show that by introducing a defined amount of spatial overlapping, the lateral resolution of LIBS images can be improved significantly below the aforementioned sensitivity threshold. For this, industrial samples of galvanized steel are investigated and compared.