Effects of gas environment on picosecond laser ablation

The effect of gas medium on picosecond laser ablation at atmospheric pressure was studied for enhancing the quantity of mass removed. Five noble gases (He, Ne, Ar, Kr, Xe) were used in the ablation chamber and were found to influence the laser ablation efficiency significantly. The quantity of mass was measured using inductively coupled plasma (ICP) atomic emission spectroscopy (AES). Spectral emission intensity in the ICP is directly related to the quantity of mass ablated. The performance of laser ablation in different gases correlates with the ionization potential of the gas. There is an enhancement of emission intensity for laser sampling in He relative to Ar. Plasma shielding is discussed as a possible mechanism for the enhancement. (C) 1998 Elsevier Science B.V.