Abstract: A method spectrally and temporally characterizing the fluorescence and/or phosphorescence of a material includes using a frequency-domain cross-correlation fluorometer-phosphorimeter employing an interferometer. A flux-modulated excitation signal is used to excite the material. An interferometer is used to generate an optical path difference (OPD) between portions of an emission signal produced by the excited material to obtain an optical interference signal. The optical interference signal is detected by a heterodyning detection system to determine phase shift and demodulation of the emission signal relative to the excitation signal. Phase shift and demodulation data are acquired at a series of OPD values generated by the interferometer and at a plurality of light source flux-modulation frequencies at each OPD to spectrally and temporally resolve the emission signal.