Fluorescence lifetime imaging microscopy method having time-correlated single-photon counting, which method permits higher light intensities

A microscope for implementing a fluorescence lifetime imaging microscopy method with time-correlated single photon counting, the microscope comprising:

• a light source configured to excite a sample with excitation light pulses to emit fluorescence photons, with a measurement interval being defined between each two successive excitation light pulses,
• a detector configured to detect the fluorescence photons and to generate an analog detector signal representing the detected fluorescence photons, and
• a processor configured to determine detection times at which the fluorescence photons are detected by the detector within the respective measurement intervals based on the detector signal so as to compute at least one value characterizing fluorescence decay behavior based on the detection times, and to perform imaging based on the at least one value,
• wherein the processor is configured to sample the analog detector signal within a respective one of the measurement intervals in a plurality of sampling intervals and to convert the analog detector signal to a sequence of discrete signal values associated with the sampling intervals, and to determine, based on the sequence of discrete signal values associated with the respective measurement interval, whether more than a predefined number of fluorescence photons greater than or equal to 1 has been detected within the respective measurement interval, and
• wherein the processor is configured to discard the respective measurement interval for which it has been determined that more than the predefined number of fluorescence photons has been detected in the step of determining the at least one value characterizing the fluorescence decay behavior.