We investigated the effect of additional laser irradiation on the energy state of a laser-ablated plume from a graphite target. Optical emissions from the plume were observed by a spectrometer equipped with an intensified charged couple device (ICCD) immediately after additional laser irradiation at various time delays relative to the ablation. The emission intensity from atomic carbon, ionic carbon, C-2 and C-3 increased when an ArF excimer laser irradiated the carbon plume. The atomic carbon absorbed the ArF excimer laser resonantly and was ionized. Using the fourth harmonic output of an Nd:YAG laser or a KrF excimer laser, the emission intensity from C-2 and C-3 only increased. However, no emission spectra change was observed with additional irradiation fundamental output of an Nd:YAG laser. The emission intensity from the atomic and ionic carbon and carbon clusters (C-2 and C-3) following ArF excimer laser irradiation of the plume was stronger than that using any other lasers. (C) 2002 Elsevier Science B.V All rights reserved.