Figure 1.

Example of TS-FRET signals, illustrating the relationship between TS and SPC signals. (A) The TS-FRET signal records arrival times of every single photon on the donor (green) and the acceptor (red) detector channels. (Inset) Experimental observables t, Δt, and ρ. (B and C) The SPC signals are made by binning photons with a fixed time period. (D) The time bin-based FRET trajectory (blue) is calculated from the SPC signals. The true FRET trajectory (purple) changes stepwise, showing the typical feature of single-molecule signals. (Color online.)