  Adiabatic passage techniques allow the generation of single photons which are
very long compared to the typical detector time resolution. Therefore the
detection time of a photon can be measured within the duration of the
single-photon wavepacket. As a consequence, two-photon interference can be
investigated in a time-resolved manner, i.e., the coincidence rate can be
measured as a function of the time between photodetections. The theoretical
analysis shows that this method not only gives information about the duration
of single photons, but also about their coherence time. Here we discuss how to
use this method for a spectral or temporal characterization of a single-photon
source.
