Laser-tissue interaction with high-power fiber lasers operating in the mid-infrared wavelength region

We describe the results of preliminary studies on the interaction of continuous wave (cw), mid-infrared fiber laser light and soft biological tissues. An Er, Pr:ZBLAN fiber laser operating at a wavelength of 2.71 μm was used at 800 mW output power, a Tm-doped silica fiber laser at 1.98 μm provided up to 5 W output power, and a Yb:Er-doped silica fiber laser at 1.5 μm was used at 800 mW output power. Surface changes in tissue samples are described qualitatively and quantitatively, ablation velocity in tissue is measured, where observed, at the 800 mW power level, and sample sections are described with reference to histologically recognisable markers of thermal damage. The basic science described prepares the way toward ultimate clinical evaluations and applications of these new laser sources.