Femtosecond laser plasma plume characteristics in the nanojoule ablation regime

Journal Article · Tue May 14 04:00:00 EDT 2013 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4804329· OSTI ID:22162902

Banerjee, S. P.; Chen, Zhijiang; Fedosejevs, R. ^[1]

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1. Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G2V4 (Canada)

Laser ablation of chromium with nanojoule energy UV femtosecond pulses under background pressure conditions between 0.3 Torr and 700 Torr is studied and the corresponding plasma plume images at different times after irradiation are measured. The ablation focal spot is less than or the order of a micron when 170 nJ of laser pulse energy is used. This low pulse energy leads to short lifetimes of the plasma of the order of tens of nanoseconds. The plume shape changes with ambient pressure due to the collision with background gas. An axially stretched plume changes to a more circular plume as the pressure increases. In addition, a separation of the ionic and atomic components is observed at lower pressure. These two components move at significantly different velocities as well. The plasma plume expands at almost constant velocity at very low pressure but exhibits significant deceleration at higher pressure reaching an asymptotic stopping distance. Plume images are also obtained near the ablation threshold pulse energy. The plume characteristics are compared to different models of plume expansion.

• OSTI ID: 22162902
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 18 Vol. 113; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABLATION
ACCELERATION
ASYMPTOTIC SOLUTIONS
CHROMIUM
COLLISIONS
COMPARATIVE EVALUATIONS
EXPANSION
IMAGES
IRRADIATION
LASER RADIATION
LIFETIME
LIGHT TRANSMISSION
PLASMA DIAGNOSTICS
PULSES