A new fiber-optic-based fluorescence lifetime instrument is described which is useful for the study of complex fluorescence decay kinetics. The new instrument consists of a multifrequency phase fluorometer coupled to a fiber-optic probe. To demonstrate the power of the new instrument, we show results for the unequivocal resolution of single, double, and triple exponential decays of fluorescence. In addition, spectral coverage in the ultra-violet and visible regions is possible, and lifetimes from approximately 200 ns to 150 ps are easily determined for samples as dilute as 0.1 μM.
Frank V. Bright, "A New Fiber-Optic-Based Multifrequency Phase-Modulation Fluorometer," Appl. Spectrosc. 42, 1531-1537 (1988)