Nanosecond laser coupling for increased filament ablation.

Laser filaments can project intensities sufficient to ablate materials at long ranges, but the clamping of a filament's intensity to ∼1014  W/cm2 limits the effective ablation of targets with which the laser pulses interact. We seek to identify regimes in which auxiliary radiation can be used to augment the ablation created by single filaments. In this work, the combination of an 800 nm, 50 fs beam at single filament intensity and a 1064 nm, 8 ns laser pulse is studied. The ablation of GaAs is quantitatively evaluated for varying interpulse delays. Under optimum conditions, an ∼threefold increase in the ablation is observed. The metrology and surface features of the resultant ablation craters are examined to gain insight on the mechanisms of ablation in the dual-pulse cases.