  A theory of pump-probe spectroscopy is developed in which optical fields
drive two-photon Raman transitions between ground states of an ensemble of
three-level $\Lambda $ atoms. Effects related to the recoil the atoms undergo
as a result of their interactions with the fields are fully accounted for in
this theory. The linear absorption coefficient of a weak probe field in the
presence of two pump fields of arbitrary strength is calculated. For subrecoil
cooled atoms, the spectrum consists of eight absorption lines and eight
emission lines. In the limit that $\chi_{1}\ll \chi_{2}$, where $\chi_{1}$ and
$\chi_{2}$ are the Rabi frequencies of the two pump fields, one recovers the
absorption spectrum for a probe field interacting with an effective two-level
atom in the presence of a single pump field. However when $\chi_{1}\gtrsim
\chi_{2}$, new interference effects arise that allow one to selectively turn on
and off some of these recoil induced resonances.
