Repetitive laser pulses can be applied for one laser spot to precisely remove a selected amount of sample mass with each laser pulse. By collecting LIBS spectra during repetitive laser pulsing, the elemental content at different sample depths can be obtained.

The image on the left shows the crater depths at different laser pulse numbers for Ni-P layer on top of Al-Mg substrate used in storage media. Each pulse ablated ~ 100 nm thickness of the film, allowing 100 point depth profiling measurements for 10 micron Ni-P film. The image on the right shows the comparative LIBS spectra at pulse numbers 5 and 110. The pulse #110 detects a strong presence of Al due to the ablation reaching down to the Al-Mg substrate.