Absolute depth laser-induced breakdown spectroscopy-stratigraphy with non-scanning single spot optical coherence tomography

LIBS is a proven method for elemental analysis. It needs little to no sample preparation and relies solely on optical access to the sample. LIBS has therefore been handled as a promising analytical method for layered or structured samples with the potential to replace metallurgic cross-sections followed by SEM/EDX raster screenings. Due to the strong dependency of the ablation process on changing crater geometries, laser fluence, and plasma dynamics (e.g. laser absorption and scattering by the plasma, material dependent optical depth, reflecting coefficients, scattering processes, etc.), attributing an absolute depth to the number of laser pulses applied to the sample is not trivial. In this work, we show absolute depth recognition based on single-spot, non-scanning optical coherence tomography on LIBS craters produced with a standard LIBS setup. The results are verified with the use of ex-situ (electron-)microscopic techniques.