Dynamics of laser desorption and ablation of metals at the threshold on the femtosecond time scale
The dynamics of the laser-ablation (-desorption) process of metals (Al, Ag, Fe, and Ni) initiated by 30 fs laser pulses has been investigated by interferometric time-resolved pump-probe measurements. It is postulated that a sufficiently high density of hot electrons is essential for achieving desorption of metal ions. In addition, we have observed a new and unexpected behavior characterized by delayed ablation for a pump-probe beam delay in the range of several ps for Al, Ni, and Fe. This second peak is attributed to the development of a liquid surface layer developing after a few ps. Molecular dynamics simulations support this assumption.
Schmidt
V
Institut fur Allgemeine Physik, Technische Universitat Wien, Wiedner Hauptstrasse 8-10, 1040 Wien, Austria.
Husinsky
W
Betz
G