Study of excitation transfer in laser dye mixtures by direct measurement of fluorescence lifetime

By directly measuring the donor fluorescence lifetime as a function of acceptor concentration in the laser dye mixture rhodamine 6G-Cresyl violet, we found that the Stern-Volmer relation is obeyed, from which the rate of excitation transfer is determined. The experimental results indicate that the dominant mechanism responsible for the efficient excitation transfer is that of resonance transfer due to long-range dipole-dipole interaction.