Coherent population transfer in multilevel systems with magnetic sublevels. I. Numerical studies

The technique of stimulated Raman adiabatic passage has become an established procedure for producing complete population inversion in atoms or molecules via application of Stokes and pump pulses in a counterintuitive sequence. We discuss here some of the new and important phenomena that arise when some of the states involved have nonzero angular momentum, the field polarization directions have no simplifying symmetries, and Zeeman splitting lifts the magnetic sublevel degeneracy. We consider the effects of the linkage structure of the Hamiltonian, the effects of various polarization directions, and the effects of various choices for carrier frequencies, as expressed by detunings from single-photon resonance. In particular, we consider an example with angular momentum J=0↔J=1↔J=2 in which nine magnetic sublevels occur. We show that under suitable conditions it is possible, simply through the appropriate tuning of pump and Stokes carrier frequencies, to place the entire population into any specified single magnetic sublevel