2Privolzhskiy Medical Research University, 603005 Nizhny Novgorod, Russia
* To whom correspondence should be addressed.
Received September 3, 2018; Revised September 22, 2018; Accepted September 22, 2018
Classic time-correlated single photon counting (TCSPC) technique involves detection of single photons of a periodic optical signal, registration of the photon arrival time in respect to the reference pulse, and construction of photon distribution with regard to the detection times. This technique achieves extremely high time resolution and near-ideal detection efficiency. Modern TCSPC is multi-dimensional, i.e., in addition to the photon arrival time relative to the excitation pulse, spatial coordinates within the image area, wavelength, time from the start of the experiment, and many other parameters are determined for each photon. Hence, the multi-dimensional TCSPC allows generation of photon distributions over these parameters. This review describes both classic and multi-dimensional types of TCSPC microscopy and their application for fluorescence lifetime imaging in different areas of biological studies.
KEY WORDS: fluorescence lifetime imaging, time-correlated single photon counting, Förster resonance energy transfer, metabolism, phosphorescence, luminescence