Fundamental Study of Evaporation Factors in Laser Ablation of Metals

Abstract

To investigate the evaporation factor in the laser ablation process, we controlled the laser power and ambient pressure in a nitrogen atmosphere, ablated AgPd, and attempted to observe the ablation plume. 5 minutes of laser irradiation was applied to AgPd, and the evaporation rate was calculated by dividing the evaporation amount by the irradiation time. The evaluation was made. The laser beam was scanned over the target at an angle of 45 degrees by moving the eccentric rotating mirror type galvanometer scanner and the X-Y table on which the target was installed. At the irradiation point, a luminescence called a plume was generated by the plasma of evaporated atoms of the target and ambient gas. The evaporation rate increased with increasing laser power and ambient pressure. In laser power control, the size of the plume was proportional to the evaporation rate, while in pressure control, the evaporation rate decreased with decreasing ambient pressure, but the plume increased. These results indicate that increasing laser power and ambient pressure are effective in increasing evaporation rate, but there is no correlation between plume size and evaporation rate.