Influence of pulse duration on ultrashort laser pulse ablation of biological tissues

Ablation characteristics of ultrashort laser pulses were investigated for p ulse durations in the range of 130 fs-10 ps. Tissue samples used in the stu dy were dental hard tissue (dentin) and water. We observed differences in a blation crater morphology for craters generated with pulse durations in the 130 fs-1 ps and the 5 ps-10 ps range. For the water experiment, the surfac e ablation and subsequent propagation of stress waves were monitored using Mach-Zehnder interferometry. For 130 fs-1 ps, energy is deposited on the su rface while for longer pulses the beam penetrates into the sample. Both stu dies indicate that a transition occurs between 1 and 5 PS. (C) 2001 Society of Photo-Optical Instrumentation Engineers.