  The scattering of a single photon with sufficiently high energy can cause a
recoil of a motional scatterer. We study its backaction on the photon's
coherent transport in one dimension by modeling the motional scatterer as a
two-level system, which is trapped in a harmonic potential. While the
reflection spectrum is of a single peak in the Lamb-Dicke limit, multi-peaks
due to phonon excitations can be observed in the reflection spectrum as the
trap becomes looser or the mass of the two-level system becomes smaller.
