  We investigate the question whether Michelson type interferometry is possible
if the role of the beam splitter is played by a spontaneous process. This
question arises from an inspection of trajectories of atoms bouncing
inelastically from an evanescent-wave (EW) mirror. Each final velocity can be
reached via two possible paths, with a {\it spontaneous} Raman transition
occurring either during the ingoing or the outgoing part of the trajectory. At
first sight, one might expect that the spontaneous character of the Raman
transfer would destroy the coherence and thus the interference. We investigated
this problem by numerically solving the Schr\"odinger equation and applying a
Monte-Carlo wave-function approach. We find interference fringes in velocity
space, even when random photon recoils are taken into account.
