High-sensitivity 648x484-pixel CMOS image sensor for wide-field FLIM with four simultaneous time gates

We report wide-field time-domain fluorescence lifetime imaging (TD-FLIM) using a high-photosensitivity 648x484- pixel time-resolved CMOS image sensor with four simultaneous time gates. The advantages of this image sensor are high spatial resolution, high quantum efficiency and high photon rate. In this report, we verified the applicability of a 648x484-pixel range imaging sensor developed in our laboratory for FLIM. In the measurements, four time-resolved images are obtained simultaneously. To improve the temporal sampling resolution, sub sampling is performed. The performance was compared with that of our previously developed 128x128-pixel TD-FLIM CMOS image sensor. The data was analyzed by the phasor method at 20MHz. The measured average fluorescence lifetimes for the new and previous sensors were 8.52 ns and 8.26 ns, and the standard deviations were 0.74 ns and 0.56 ns, respectively. We have achieved higher signal-to-noise ratios as well as high spatial resolution. Finally, this image sensor was used to perform two-dimensional imaging of the fluorescence lifetime of fluorescent acrylic plates.