It remains a big challenge to theoretically predict the material removal mechanism in femtosecond laser ablation. To bypass this unresolved problem, many calculations of femtosecond laser ablation of nonmetals have been based on the free electron density distribution without the actual consideration of the phase change mechanism. However, this widely used key assumption needs further theoretical and experimental confirmation. by combining the plasma model and improved two-temperature model developed by the authors, this study focuses on investigating ablation threshold fluence, depth, and shape during femtosecond laser ablation of dielectrics through nonthermal processes (the Coulomb explosion and electrostatic ablation). The predicted ablation depths and shapes in fused silica, by using (1) the plasma model only and (2) the plasma model plus the two-temperature equation, are both in agreement with published experimental data. The widely used assumptions for threshold fluence, ablation depth, and shape in the plasma model based on free electron density are validated by the comparison study and experimental data.
L. Jiang and H. Tsai, "A Plasma Model Combined with an Improved Two-Temperature Equation for Ultrafast Laser Ablation of Dielectrics," Journal of Applied Physics, American Institute of Physics (AIP), Nov 2008.
The definitive version is available at http://dx.doi.org/10.1063/1.3006129
Mechanical and Aerospace Engineering
Ministry of Science and Technology of the People's Republic of China. 111 Project
Air Force Research Laboratory (Wright-Patterson Air Force Base, Ohio)
National Natural Science Foundation (China)
National Science Foundation (U.S.)
Keywords and Phrases
Ionisation; Plasma Light Propagation; Laser ablation; Plasma density
Article - Journal
© 2008 American Institute of Physics (AIP), All rights reserved.