Ultrashort double pulse laser ablation of metals

The peculiarities of laser microablation and plasma re-heating with ultrashort (50 fs-10 ps) double pulses were studied. Three regimes of laser/metal target interaction were observed as a function of double-pulse delay: without any plasma shielding (Deltat(12)less than or equal to1 ps), intermediate (1less than or equal toDeltat(12)less than or equal to10 ps) and with total plasma shielding (from 10 to 250 ps). The optimal plasma re-heating regime with the highest plasma intensity and reproducibility was determined to correspond to the double pulses delay of 100-200 ps. The pulses in the 50 fs-2 ps range were observed to give approximately the same ablation efficiency with a metal target. (C) 2003 Elsevier B.V. All rights reserved.