Effect of air breakdown with a focusing lens on ultrashort laser ablation

The effect of air breakdown on ultrashort laser ablation is investigated in this letter using an integrated simulation method on atomistic level. The generation of air breakdown with different laser peak power densities in the range from 10(13) to 10(16)W/cm(2) and various focusing conditions is analyzed. Air breakdown is generated directly from laser energy absorption through avalanche ionization at a high power density (over 10(14)W/cm(2)), while at a lower power density, air breakdown is assisted by a metal target near the focal region. The laser energy loss due to air breakdown and its effect on laser ablation are studied. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3665631]