  We propose a scheme of generating and verifying mesoscopic-level entanglement
between two atomic ensembles using non-resonant stimulated Raman scattering.
Entanglement can be generated by direct detection or balanced homodyne
detection of the Stokes fields from the two cells, after they interfere on a
beam splitter. The entanglement of the collective atomic fields can be
transferred to the anti-Stokes fields in a readout process. By measuring the
operator moments of the anti-Stokes fields, we can verify the presence of
entanglement. We model the effects of practical factors such as Stokes field
detector quantum efficiency and additive thermal noise in the entanglement
generating process, and anti-Stokes field losses in the entanglement
verification process, and find achievable regimes in which entanglement can be
verified at the levels of tens to hundreds of atomic excitations in the
ensembles.
