In ultrashort pulse (<10 ps) laser ablation of dielectrics, affected materials are first transformed into absorbing plasma with metallic properties and, then, the subsequent laser-plasma interaction causes material removals. For ultrashort-pulse laser ablation of dielectrics, this study proposes a model using the Fokker-Planck equation for electron density distribution, a plasma model for the optical properties of ionized dielectrics, and quantum treatments for electron heating and relaxation time. The free electron density distribution of the plasma within the pulse duration is then used to determine the ablation crater shape. The predicted threshold fluences and ablation depths for barium aluminum borosilicate and fused silica are in agreement with published experimental data. It is found that the significantly varying optical properties in time and space are the key factors determining the ablation crater shape. The effects of fluence and pulse duration are also studied.
L. Jiang and H. Tsai, "Plasma Modeling for Ultrashort Laser Ablation of Dielectrics," Journal of Applied Physics, American Institute of Physics (AIP), Jan 2006.
The definitive version is available at http://dx.doi.org/10.1063/1.2216882
Mechanical and Aerospace Engineering
Keywords and Phrases
Fokker-Planck Equation; Aluminosilicate Glasses; Borosilicate Glasses; Dielectric Materials; High-Speed Optical Techniques; Laser Ablation; Plasma Density; Plasma Production By Laser
Article - Journal
© 2006 American Institute of Physics (AIP), All rights reserved.