Fig. 3. Schematic of the photon detection events.

The light pink–shaded region illustrates the temporal distribution of $F_{\mathrm{t}}(t,t_{\mathrm{I}})$ in Eq. 4. The arrival times of the idler photons are blurred by the finite temporal resolution of the single-photon camera. Although not illustrated here, the fluorescence photons experience the same temporal blurring.