Investigations of Femtosecond-Nanosecond Dual-Beam Laser Ablation of Dielectrics
A multi-scale (in temporal domain) model was developed to study the ablation of dielectrics using a femtosecond (fs)-nanosecond (ns) dual-beam laser system. The model is an integration of the plasma model and improved two-temperature model for the fs laser ablation, and Fourier's law for the ns laser ablation. The model is used to investigate the ablation for dielectrics when a fs pulse is shot at the peak of a ns pulse. It is found that the fs laser pulse can result in the increase of absorption of the ns laser energy, leading to a much higher material removal rate as compared to fs laser ablation alone or ns laser ablation alone. The enhancement of ns laser energy absorption is caused by the increased electron density and the formation of a tiny crater in the material created by the fs laser pulse. The corresponding experiment using a Ti: Sapphire fs laser (Legend-F, Coherent) and a Nd: YAG ns UV laser (Avia-X, Coherent) was also conducted and the results are consistent with the modeling predictions.
H. Tsai et al., "Investigations of Femtosecond-Nanosecond Dual-Beam Laser Ablation of Dielectrics," Proceedings of the ASME 2009 2nd Micro/Nanoscale Heat & Mass Transfer International Conference, MNHMT 2009, American Society of Mechanical Engineers (ASME), Dec 2009.
The definitive version is available at http://dx.doi.org/10.1115/MNHMT2009-18188
Mechanical and Aerospace Engineering
Keywords and Phrases
Heat Transfer; Laser Pulses; Neodymium Lasers; Pulsed Laser Applications; Absorption; Laser ablation; Mass transfer; Photolithography
Article - Conference proceedings
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