  A novel laser cooling mechanism was recently demonstrated using a
narrow-linewidth optical transition. Counter-propagating laser beams are swept
in frequency to cause adiabatic transfer between a ground state and excited
state, and Doppler shifts provide time-ordering that ensures the associated
photon recoils oppose the particle's motion. We now expand this technique to
$^{87}$Rb, which has no narrow-linewidth optical transition, by using
artificially-narrow two-photon Raman transitions. The cooling mechanism is
capable of exerting large forces to compress the phase-space of the atomic
ensemble without relying on spontaneous emission, providing further support for
its potential use in cooling molecules or other particles that lack closed
cycling transitions. Because the dynamics of the adiabatic transfer are crucial
for assessing the feasibility of Raman SWAP cooling, we also develop a generic
model for Raman Landau-Zener transitions in the presence of free-space
scattering.
