MECHANICAL POTENTIALS DUE TO RAMAN TRANSITIONS

We investigate the mechanical potential of an atom due to a Raman tran sition. This is a generalization of the usual two-level dipole potenti al. With sufficiently large one- and two-photon detunings the forms of the potential and excitation probability are the same as for the two- level case, but with a scaled detuning. This allows greater effective blue detunings to be accessible with the Raman scheme. This means that with the same available laser power, atoms can move coherently in the light field for many orders of magnitude longer without spontaneously emitting. Furthermore the sign of the potential may be controlled ind ependently of the one-photon detuning.