The potential of a diagnostic technique to provide quantitative three‐dimensional (3D) density distributions of species in a low temperature laser‐produced plume is shown. An expanded, short pulse, tunable dye laser is used to probe the plume at a set time during the expansion. Simultaneous recording of two‐dimensional in‐line absorbance maps and orthogonal recording of laser induced fluorescence permits the 3D density mapping by scanning the dye laser frequency. Preliminary data, supported by a simple model, is presented for the case of Ba IIions in a YBCO plume heated by a KrF laser. ©1996 American Institute of Physics.