Fig. 2: BrightEyes-TTM characterization and validation.

a–c Single-shot precision experiment. a Temporal schematic representation: a fixed frequency SYNC clock signal and a synchronized but delayed (in a controlled way) signal. b Unified representation of the start–stop time histograms as a function of the imposed delay between the two signals. c Single start–stop time histogram for the delay denoted by the dotted white line in the middle panel. The inset shows a magnification of the histogram for a selected temporal interval, superimposed with the Gaussian fit (red line). d, e Dual-channel single-shot precision experiment. d Temporal schematic representation: a fixed frequency SYNC clock signal and a pair of synchronized signals (channel A and channel B). The delays between all three signals are fixed. e Jitter map for each pair of channels (here, 25 channels), i.e., error in the time-difference estimation between any two channels, measured as the standard deviation of a Gaussian fit of the error distribution. The diagonal of the map represents the sigma of the single-channel single-shot precision experiment. f Normalized impulse-response functions (dark colors) and fluorescein–water solution decay histograms (light colors) for the BrightEyes-TTM and DPC-230 multi-channel card. The instrument response functions (IRFs) represent the response of the whole architecture (microscope and DAQ) to a fast (sub-nanosecond) fluorescence emission. The full-width-at-half-max values are 250 ps for the DPC-230 card and 200 ps for the BrightEyes-TTM. The decay histograms are also typically referred to as start–stop time histograms or TCSPC histograms. All single-channel measurements were done with TTM channel #12, which received the photon signal from the central element of the SPAD array detector. All start–stop histograms have 48 ps granularity (bin width).