Self emission spectra of the plasma at total pressures of (a) 2*10−2 and (c) 1*10−1 mbar after arriving at the substrate, respectively 6 and 20 μs after ablation. The YO line at 597 nm is indicated with a black arrow. (b,d) Show the relative intensities of the YO line at 597 nm after different delay times for total pressures of 2*10−2 and 1*10−1 mbar respectively. The color scales correspond to subfigures (a,c), the arrivial of the plasma plume at the substrate is indicated with a dashed line.