Summary

A new method of determining fluorescence decays by the use of two beating ring dye lasers as excitation source is described. The analysis of the frequency dependence of the fluorescence demodulation of rhodamine 640 and rose bengal in ethanol, methanol and water, yielding lifetimes of 4.28 ns, 740, 525 and 80 ps, respectively, shows good agreement with previously reported values. Comparison of the lifetimes to values measured with the single-photon-counting technique underline the reliability of this new method