Time-resolved shadowgraphic study of femtosecond laser ablation of aluminum under different ambient air pressures

Journal Article · Tue Mar 01 00:00:00 EST 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3554442· OSTI ID:21538134

Zehua, Wu; Xiaonong, Zhu; Nan, Zhang

Femtosecond pulse laser ablation of aluminum under different ambient air pressures between 1 atm and 4 x 10{sup -4} Pa is investigated using a femtosecond time-resolved shadowgraphic method. It is observed that as the ambient air pressure decreases, the contact front becomes more and more distinct for a certain pressure range, demonstrating that the confinement effect of the ambient air to the ablated target material can play a critically important role in the laser ablation process. It is also found that the concentric and semicircular stripe pattern, which results from the diffraction of the probe beam by the expanding plume of a specific material state and is typically observed in the shadowgraphs for 1-2 ns delay time, gradually blurs and disappears while the ambient air pressure decreases from 1 atm to 7000 Pa. If a prepulse or a relatively large pulse pedestal exists before the main pulse, however, the stripe pattern can still be observed even though the ambient air pressure is 5 x 10{sup -4} Pa. It is thus inferred that what contributes to the formation of the unique stripe pattern is a mixture of the ejected target material and ionized background gas induced by the femtosecond laser ablation.

• OSTI ID: 21538134
• Journal Information: Journal of Applied Physics, Vol. 109, Issue 5; Other Information: DOI: 10.1063/1.3554442; (c) 2011 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABLATION
AIR
ALUMINIUM
DEPOSITS
DIFFRACTION
ELECTRON MICROSCOPY
LASER RADIATION
METABOLISM
MIXTURES
PRESSURE DEPENDENCE
PRESSURE RANGE
PULSES
SPECTRA
STRAINS
TIME DELAY
TIME RESOLUTION
COHERENT SCATTERING
DISPERSIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
FLUIDS
GASES
METALS
MICROSCOPY
RADIATIONS
RESOLUTION
SCATTERING
TIMING PROPERTIES