Femtosecond laser-assisted surface modification of tungsten with 1015 W/cm2 intensity in air and vacuum ambience

The present study deals with modification of tungsten surface with high-intensity (∼1015 W/cm2) femtosecond laser in air and vacuum surrounding. Specific findings include: (a) the applied intensities produce crater-like damages with depth ∼31.0 μm in vacuum and ∼7.2 μm in air; (b) peripheral region of the damages is diffuse in air atmosphere unlike vacuum where it is more sharply defined; (c) hydrodynamic features, while present in vacuum, are dramatically reduced in air; (d) characteristic chemical surface changes occur at the surface, and (e) plasma forms in front of the target in both surroundings. The obtained results imply that the employed intensities, in a certain sense, can be used for simulation of some processes in the fusion reactor and for highly precise material removal and tungsten surface processing (by fine tuning of given fs laser parameters).