EFFECTS OF GAS ENVIRONMENT ON PICOSECOND LASER-ABLATION

The effect of gas medium on picosecond laser ablation at atmospheric p ressure was studied for enhancing the quantity of mass removed. Five n oble gases (He, Ne, Ar, Kr, Xe) were used in the ablation chamber and were found to influence the laser ablation efficiency significantly. T he quantity of mass was measured using inductively coupled plasma (ICP ) atomic emission spectroscopy (AES). Spectral emission intensity in t he ICP is directly related to the quantity of mass ablated. The perfor mance of laser ablation in different gases correlates with the ionizat ion potential of the gas. There is an enhancement of emission intensit y for laser sampling in He relative to Ar. Plasma shielding is discuss ed as a possible mechanism for the enhancement. (C) 1998 Elsevier Scie nce B.V.