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Wide-field time-correlated single photon counting (TCSPC) microscopy with time resolution below the frame exposure time

Research output: Contribution to journalArticlepeer-review

Liisa Hirvonen, Zdeněk Petrášek, Klaus Suhling

Original languageEnglish
Article number57075
Pages (from-to)1-5
Number of pages5
JournalNuclear Instruments & Methods In Physics Research Section A, Accelerators, Spectrometers, Detectors And Associated Equipment
Published1 Jul 2015

King's Authors


Fast frame rate CMOS cameras in combination with photon counting intensifiers can be used for fluorescence imaging with single photon sensitivity at kHz frame rates. We show here how the phosphor decay of the image intensifier can be exploited for accurate timing of photon arrival well below the camera exposure time. This is achieved by taking ratios of the intensity of the photon events in two subsequent frames, and effectively allows wide-field TCSPC. This technique was used for measuring decays of ruthenium compound Ru(dpp) with lifetimes as low as 1 μs with 18.5 μs frame exposure time, including in living HeLa cells, using around 0.1 μW excitation power. We speculate that by using an image intensifier with a faster phosphor decay to match a higher camera frame rate, photon arrival time measurements on the nanosecond time scale could well be possible.

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