Time-Correlated Single Photon Counting (TCSPC) is a technique used to measure the time intervals between the arrival of single photons. It is particularly useful in fields like fluorescence microscopy and quantum optics, where precise timing is crucial. The method involves detecting photons with a sensitive detector and recording the time of each detection relative to a reference signal, allowing researchers to create detailed timing histograms. This technique enables scientists to study the dynamics of various processes at the nanoscale, such as energy transfer in molecules or the behavior of quantum dots. By analyzing the timing data, researchers can gain insights into the underlying mechanisms of these phenomena.