Coulomb explosion (CE) is identified as the mechanism of ion ejection under low fluence ultrashort pulse laser ablation of crystalline Al2O3. The ion momenta are equal during "gentle" ablation. This is explained by impulsive CE from the surface region lasting ∼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.
|Number of pages||7|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - 15 Nov 2000|