Fig. 1.

Absorption coefficient of liquid water at room temperature (22 °C) in the near-infrared range (red line). The Thulium fiber laser has been adapted to operate at 1940 nm, a wavelength close to a water absorption peak (approximatively 14 mm⁻¹). Comparatively, the wavelength of the Holmium:YAG laser (2120 nm) has a much lower absorption coefficient in liquid water (approximatively 3 mm⁻¹)