Time-resolved confocal scanning device for ultrasensitive fluorescence detection

A confocal laser-scanning microscope for ultrasensitive fluorescence lifetime imaging on surfaces is presented. The system employs a compact electronics for time-correlated single-photon counting (TCSPC), allowing for measuring fluorescence lifetime with 40 ps time resolution, and for continuously recording photon arrival times with 100 ns time resolution. Additionally developed driver electronics serve for synchronization of scanning and data acquisition, which is significant for achieving high spatial image resolution. The capabilities of the measurement system are demonstrated on imaging single molecules immobilized on glass substrates. Finally, it is shown how the TCSPC capabilities of the system can be used not only for lifetime imaging but also for multichannel measurements.