Ultrafast laser ablation of graphite

We have studied single-shot femtosecond laser ablation of graphite by combining a variety of experimental techniques including Raman spectroscopy, atomic force microscopy as well as time of flight spectrometry. The comprehensive analysis reveals insights into the ablation process by exploring the surface structure, the fluence dependence, and the structural dynamics of the detachment. The results show formation and detachment of charged carbon products (such as graphene nanoflakes) from the surface. Time-resolved measurements of ion yields and velocities reveal strong quenching and revival of Coulomb explosion as a function of delay time in the range of 100-200 fs, suggesting a displacive motion between the topmost surface layers which regulates the optical properties of the system.