Planar laser‐induced fluorescence (PLIF) is used to monitor Cu atoms and Cu2produced by excimer laser ablation of a copper target (308 nm, ≳10 J/cm2, 1–3 GW/cm2) expanding rapidly into helium background gas at pressures ranging from 10 to 100 Torr. The Cu2results from gas phase condensation of the copper atoms ablated from the target in the regions of highest Cu atom density as expected, but the maximum Cu2laser‐induced fluorescence (LIF) signal occurs significantly after the maximum of the Cu signal. Rotationally resolved excitation scans of Cu2utilizing theA–X(0,0) transition indicate that the Cu2has reached equilibrium with the 300 K background gas. An extensive search for Cu3via LIF failed, indicating that Cu3is present only in very low ‘‘steady state’’ number density in the plume. This data is explained qualitatively by a simple kinetic model. In addition to the kinetic information, it is clear from the PLIF images that viscous eddy formation becomes more pronounced as the backing gas pressure increases; however, we see no evidence of turbulence in the plume even at the highest backing gas pressure studied. The PLIF technique allows us to observe the onset of condensation directly as well as to obtain information about the expansion dynamics of the plume not easily obtainable by other means.