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Coulomb explosion in ultrashort pulsed laser ablation of Al 2 O 3

2000; American Physical Society; Volume: 62; Issue: 19 Linguagem: Inglês

10.1103/physrevb.62.13167

1095-3795

Razvan Stoian, David Ashkenasi, A. Rosenfeld, E. E. B. Campbell,

Laser Material Processing Techniques

Coulomb explosion (CE) is identified as the mechanism of ion ejection under low fluence ultrashort pulse laser ablation of crystalline ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}.$ The ion momenta are equal during ``gentle'' ablation. This is explained by impulsive CE from the surface region lasting \ensuremath{\sim}1 ps. The onset of ``strong'' ablation leads to a decrease in the measured ion velocities. The kinetic energies rather than the momenta of the ions become equal. This regime is associated with strong plasma light emission and crater formation.