Observation of continuum optical emission from laser-ablation carbon plumes

We observed continuum optical emission from carbon plumes produced by laser ablation of a graphite target. Two types of continuum emission were observed: a spiky emission just after the irradiation of the laser pulse and a delayed component observed in ambient He gas. It was shown by optical emission imaging spectroscopy and laser-induced fluorescence (LIF) imaging spectroscopy that the delayed continuum emission grew in the region where the loss of C2 was significant. This result suggests that the delayed continuum emission is originated from clustering reactions among carbon species in the plume.