Abstract

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.

Department(s)

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

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2006 American Institute of Physics (AIP), All rights reserved.

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