Fluorescence decay measurement via modulated gain spectroscopy

The ability to obtain a stable tunable picosecond pulse train from a synchronously pumped dye laser is shown to permit the use of modulated gain spectroscopy to study the lifetime, spectral, and concentration-dependent behavior of fluorescent species. The fluorescence of rhodamine-B in ethylene glycol at concentrations from 3μM to 5mM was observed over the range from 570 to 640 nm; a fluorescence lifetime of 2.2 ns was obtained.