 Much more information can be obtained with time-resolved fluorescence anisotropy where the decay time, residual anisotropy and rotational correlation time can all be determined from fitting the anisotropy decay.Typically a vertically pulsed laser source is used for excitation and timing electronics are added between the start pulses of the laser (start) and the measurement of the fluorescence photons (stop).The technique Time-Correlated Single Photon Counting (TCSPC) is typically employed.