Ultrashort pulsed laser ablation and stripping of freeze-dried dermis

Plasma-mediated laser ablation and dissection of freeze-dried human dermis using an ultrashort pulsed laser of pulse width 900 fs and wavelength 1,552 nm were investigated. The surface ablation line width and depth in relation to irradiation fluence and pulse overlap rate were characterized and measured by scanning electron microscopy. The ablation threshold fluence for freeze-dried dermis was determined as 8.32 J/cm² and the incubation factor subject to pulse train irradiation was found to be 0.54. Histological examination showed no thermal damage with single line ablation. Even with multiline ablation, thermal damage was insignificant and the lateral damage zone was generally within 10 µm with 100 continuously repeated line scans. Ultrashort pulsed laser ablation of the interior of dry dermal tissue was shown to strip thin dermal slices with different thicknesses ranging from 20 to 40 µm.