Fundamental processes in nanosecond pulsed laser ablation of metals in vacuum
- 17 March 2008
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review A
- Vol. 77 (3), 032904
- https://doi.org/10.1103/physreva.77.032904
Abstract
Velocity and kinetic energy distributions (VDs, KEDs) of metal ions generated by nanosecond (ns) pulsed laser ablation under high vacuum have been determined using an electrostatic analyzer plus time-of-flight coupled system. A number of metal and alloy targets, principally involving Fe and Ni, have been studied at different laser fluences. At low fluence, the ion distributions have been shown to fit single Maxwell-Boltzmann-Coulomb (MBC) distributions; for medium and higher fluences, each ion distribution is found to comprise that of the surviving “precursor” ion, itself, overlapped with sidebands which arise from ion-electron recombination and/or ionization. The so-called surviving “precursor” ion of a distribution is that which underwent no change of charge. The Coulomb velocities of the surviving “precursor” ions and those of the ion products resulting from ion-electron collisions have been compared. Ion velocities are correlated with the local electric field resulting from ejection of the photoelectrons following laser ablation. Under identical conditions of laser fluence, the ions are seen to experience an electrical field nearly independent of their charge. The transit times of ions in the plasma have been estimated to be of the order of . An overall quantitative mechanism for metal ablation on this basis is presented, including the ejection time for photoelectrons and differences in ion distributions resulting from employing laser pulses in the nanosecond (ns) and femtosecond (fs) regimes.
Keywords
This publication has 19 references indexed in Scilit:
- Particle emission from tantalum plasma produced by 532nm laser pulse ablationJournal of Applied Physics, 2006
- Energy distribution of particles ejected by laser-generated aluminium plasmaNuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2006
- Investigations on pulsed laser ablation of Sn at 1064 nm wavelengthPlasma Sources Science and Technology, 2006
- Dual beam spectrometer using laser-induced breakdown spectroscopyReview of Scientific Instruments, 2004
- Generation of extreme high laser intensities in plasmaCzechoslovak Journal of Physics, 2004
- Quantitative micro-analysis by laser-induced breakdown spectroscopy: a review of the experimental approachesSpectrochimica Acta Part B: Atomic Spectroscopy, 2002
- Laser Processing and ChemistryAdvanced Texts in Physics, 2000
- Fundamentals and Applications of Laser-Induced Breakdown SpectroscopyCritical Reviews in Analytical Chemistry, 1997
- Applications of Laser-Induced Breakdown SpectrometryApplied Spectroscopy Reviews, 1997
- Ultrafast dynamics of laser-excited electron distributions in siliconPhysical Review Letters, 1994