Heat-affected zone and ablation rate of copper ablated with femtosecond laser

Journal Article · Tue Mar 15 04:00:00 EST 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1852692· OSTI ID:20668257

Hirayama, Yoichi; Obara, Minoru ^[1]

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1. Department of Electronics and Electrical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

We describe the experimental and molecular dynamics simulation study of crystalline copper (Cu) ablation using femtosecond lasers. This study is focused on the heat-affected zone after femtosecond laser ablation and the laser ablation rate. As a result of the x-ray diffraction measurement on the ablated surface, the crystallinity of the surface is partially changed from a crystal structure into an amorphous one. At the laser fluences below the ablation threshold, the entire laser energy coupled to the Cu target is absorbed, while during the fluence regime over the threshold fluence, the ablation rate depends on the absorption coefficient, and the residual energy which is not used for the ablation, is left in the Cu substrate. The heat-affected zone at the fluences below the threshold is estimated to be greater than that over the threshold fluence. In addition, the laser ablation of Cu is theoretically investigated by a two-temperature model and molecular dynamics (MD) simulation to explain the heat-affected zone and ablation rate. The MD simulation takes into account the electron temperature and thermal diffusion length calculated by the two-temperature model. Variation in the lattice temperature with time and depth is calculated by the MD simulation coupled with the two-temperature model. The experimental ablation rate and the heat-affected zone are theoretically well explained.

• OSTI ID: 20668257
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 6 Vol. 97; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABLATION
ABSORPTION
COPPER
CRYSTAL STRUCTURE
ELECTRON TEMPERATURE
HEAT AFFECTED ZONE
LASERS
MOLECULAR DYNAMICS METHOD
SIMULATION
SUBSTRATES
SURFACES
THERMAL CONDUCTIVITY
THERMAL DIFFUSION
THERMAL DIFFUSIVITY
X-RAY DIFFRACTION