  We give a theoretical description of a coherently driven opto-mechanical
system with a single added photon. The photon source is modeled as a cavity
which initially contains one photon and which is irreversibly coupled to the
opto-mechanical system. We show that the probability for the additional photon
to be emitted by the opto-mechanical cavity will exhibit oscillations under a
Lorentzian envelope, when the driven interaction with the mechanical resonator
is strong enough. Our scheme provides a feasible route towards quantum state
transfer between optical photons and micromechanical resonators.
