A subnanosecond time-resolved fluorescence lifetime spectrometer applying laser diodes

Since the first application of laser diodes (LD) for the determination of f luorescence lifetimes in our group in 1995, great technical improvements ha ve been made to increase the time resolution of the apparatus. Using the ph ase fluorometric method, measurements down to 100 ps are now possible. Valu es can be measured in steps of 10 ps with good reproducibility using a high -frequency signal generator and a GHz digital storage oscilloscope. No addi tional optical equipment is necessary for this new method. Following an eas y calibration procedure, results are available within one minute without an y adjustments. The components of the new apparatus including light source, sample chamber for standard fluorescence cuvettes, and detection unit are s ituated in a 12 x 13 x 9 cm setup. The apparatus was tested with different florophores, and the results correlate very well with blown values in the r ange of 0.1 to 1000 ns.