Laser induced fluorescence measurement of plasma plume during pulsed laser deposition of diamond-like carbon

Dynamics of carbon ablation plasma plume during the preparation of diamond-like carbon films by KrF excimer pulsed laser deposition was investigated using laser induced fluorescence (LIF) and optical emission spectroscopy. LIF signal from C₂ molecule (Swan band, d ³∏_g - a ³∏_u) was detected using a photomultiplier tube and an intensified CCD camera. Temporal evolution and spatial distribution of C₂ molecules in the ablated plume were measured as a function of laser energy density and ablation area. LIF intensity is found to be weaker in the central part of the plume than that at the periphery at incident energy greater than 6 J/cm². It is conjectured that some of C₂ molecules are dissociated by collision with energetic species in central part of the ablation plume. Dynamics of ablation plasma plume is strongly dependent on the size of ablated area.