Low energy femtosecond pulsed laser ablation of Nd:YAG laser crystal in high-pressure oxygen and nitrogen background gas

Abstract

Low-energy femtosecond pulsed laser was utilized to ablate Nd:YAG laser crystal in a high-pressure oxygen and nitrogen background gases. Only minute amounts of neodymium, yttrium, and aluminum were detected in the deposited material due to the thermalization resulting from low laser pulse energy and significant scattering caused by the high background gas pressure. We used a collision-based model and peak-fitting of the plume angular distribution to explain the result. The collision-based model was used to explain and determine the probability distribution of the elements arriving from the target to the substrate. The magnitude of the probability distribution obtained with O2 gas is higher compared to N2 gas owing to the former’s higher collision frequency. The peak-fitting method of the angular distribution provided better approximations of the ratio of atoms arriving after ablation as compared to collision-based model. Further improvements can be carried out to better predict the deposited material ratio.