Incubation of laser ablation in fused silica with 5-fs pulses

The threshold fluences for laser-induced damage of fused silica with single 5-fs pulses from a Ti:sapphire laser system were determined by extrapolating the ablated volume to zero. These thresholds are about 4 times as high as the values previously obtained from multi-shot experiments. This result is interpreted in terms of an irreversible modification of the original material below the single-shot threshold (incubation). Received: 14 June 1999 / Accepted: 24 June 1999 / Published online: 8 September 1999