Abstract: A method and device are disclosed for expanding the field of application of florescent correlation spectroscopy. The device has a confocal optical structure, a pulsed laser for excitation and components for detection and evaluation of measuring signals for time-correlated single photon counting. The data is registered in such a way that for each detected photon, detection time is recorded in microseconds while fluorescence delay time is recorded in nanoseconds. The information on each detected photon is used to assign parameters determined by time-correlated single photon counting to each detected photon and to create correlation functions from the determined parameters arising therefrom. Correlation functions of parameters or selective correlation functions, e.g. for fluorescence burning life, are thus obtained.