Detection of Intensity Change Points in Time-Resolved Single-Molecule Measurements

We present a method for the analysis of optical single molecule emission data that exhibit discrete intensity
jumps. This new method uses a generalized likelihood ratio test that determines the location of an intensity
change point based on individual photon arrival times. This test is applied recursively to an entire single
molecule intensity trajectory, thus finding each change points. Expectation−maximization clustering and the
Bayesian information criterion is then used for accurate determination of the true number of states accessible
to the system. This procedure allows rigorous and quantitative determination of intensity change points without
the artificial time resolution limitations that arise from binning and thresholding.