Transient fluorescence spectroscopy of terbium doped dipicolinic acid: a fluorescence lifetime measurement technique

An innovative fluorescence lifetime technique, called transient fluorescence spectroscopy, has been developed and applied toward the determination of the fluorescence lifetimes (a value near 1 ms) of terbium doped dipicolinic acid (DPA-Tb). This different lifetime measurement technique uses a high-pulse-repetition-frequency (8 kHz) pulsed UV laser excitation source and a slow modulated chopper (50to1000 Hz) to produce the modulated emission intensity from the DPA-Tb, and compares these to a theoretical transient solution of the population rate equations for the DPA-Tb energy levels. Curve fitting of the transient solution of the modulated emission intensity to that obtained experimentally yielded a value for the fluorescence lifetime.