The two-color fluorescence depletion process of Rhodamine 6G in PMMA matrixes was investigated using nano- and picosecond lasers. Erase-lasers of 1064 and 599 nm depleted the fluorescence from the S, state. Fluorescence depletion with 1064 nm was analyzed by the up-conversion from state S, to S,, while that with 599 nm was simulated based on both the up-conversion and the stimulated emission. A three-state model describes this process due to a nanosecond laser well, while it could not reproduce that by picosecond lasers. Significant contributions of vibrational relaxation in S, and re-absorption from So are suggested in the picosecond region. (c) 2005 Elsevier B.V. All rights reserved.