Emission and expansion features of ns and fs laser ablation plumes in an ambient environment

We investigated the emission and hydrodynamic expansion dynamics of ns and fs laser ablated metal plasmas in the presence of an ambient with pressures ranging from vacuum to atmospheric levels. The role of background pressure on spectral emission features, absolute line intensities, signal to background ratios, plume hydrodynamics, and ablation craters were studied. The structure and dynamics of both ns and fs plumes obtained from optical diagnostic tools were compared to continuum hydrodynamic model (CFD) results.