Time-Resolved Observation of the Ablation Plasma Plume Dynamics during Nanosecond Laser Micromachining

The dynamics of UV nanosecond laser generated ablation plasma plume expanding in ambient air was investigated. The time-resolved images of the forming and expanding ablation plume were captured. Using the captured images the initial velocity of the plasma was found to vary from 6·10³ m/s to 7·10³ m/s depending on the laser pulse fluence. The plasma expansion parameters obtained by us were compared with those predicted by shockwave model and drag model. It was found that drag model better describes plasma expansion in our experiment.