Multi-structuring and molecular formation phenomena in laser produced plasmas

Angular and time-resolved measurements were performed by implementing the Langmuir probe technique and space-and time-resolved optical emission spectroscopy (OES) for the investigations of transient plasmas generated by ns-laser ablation of Ag in various background gases.   The aim of this work was to understand the inner mechanism of ablation plasma dynamics by controlling the ionic energy distribution during the deposition process. The novelty of the study comes from recording also the floating potential in all conditions. This approach allowed us to showcase a multiple structuring of the Ag laser produced plasmas and to reconstruct the ions energy distribution. The structuring is seen in the ionic part of the collected current and confirmed by the fast electrons distribution which matched the ionic one. Each structure characterizes an ionization state of the Ag ions, results confirmed by optical emission spectroscopy along the main expansion axis and discussed in the framework of multiple double layer formation during plasma expansion. Complementary, OES allowed the spatial and temporal monitoring of visible and UV emission of the plasma. The nature of each gas influences the emission in a unique manner corelated with the data from the electrical measurements. In each of the investigated conditions thin films were deposited and had their properties corelated with the ones of the plasma. A special case was found for Ag in O2 where we show the scenario for AgO molecule formation and its impact onto the plasma energy.

Meeting ID: 766 2822 0063
Passcode: b78UA4