Nanosecond pulsed laser induced fluorescence : a powerful tool to probe atomic and molecular plasmas kinetics

Various methods have been used to investigate the excitation kinetics as well as neutral species chemistry for mozaic of different plasmas conditions in the last decades and past century. In this contribution we will present a direct method to probe the interplay between various species in a low pressure microwave plasma. Short monochromatic photons pulse of 5-10 ns are focused in the plasma and used to selectively populate one Ar 4p state from an Ar 4s metastable state. The cascade kinetics response through the Argon excitation space (as well as for analytes present in the plasma phase) is then observed in real time while looking at selected atomic or molecular transitions. Experiments were carried on for pure Ar plasmas as well as Ar with small admixture of N2.