Laser-induced spallation in diamond-like carbon films

Laser-induced multilevel spallation in diamond-like carbon films is observed and studied for a wide range of laser parameters (λ=539, 800, 1064, and 1078 nm; τ=100 fs, 300 ps, 10 ns, and 150 ns; E>0.1 J/cm2). Laser irradiation causes the detachment and removal of material layers, whose lateral size is comparable with the irradiated area and whose thickness of 10–200 nm is much less than the DLC film thickness. The influence of the laser parameters on the thickness, size, and number of removed layers is examined. A qualitative explanation of laser-induced spallation in DLC films is proposed, which is based on the fact that the absorbed laser pulse produces a rapidly expanding surface layer of modified structure and reduced density.