Laser-induced spallation in diamond-like carbon films

Laser-induced multilevel spallation in diamondlike carbon films is observed and studied for a wide range of laser parameters (lambda = 539, 800, 1064, and 1078 nm; tau = 100 fs, 300 ps, 10 ns, and 150 ns; E > 0.1 J/cm(2)). 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.