Stability, adiabaticity and transfer efficiency in a nonlinear Λ-system

Abstract

We investigate the relationship between stability, adiabaticity and transfer efficiency in a Λ-type atom-molecule coupling system via a nonlinear stimulated Raman adiabatic passage. We find that only when the pump and control lasers overlap in time domain, the coherent population trapping (CPT) state could become unstable. If the overlapping time of the two lasers is short so that unstable growth of the deviation from the CPT state is negligible, then good adiabaticity of the CPT state could be maintained even in the unstable region. In this case, a high atom-molecule transfer efficiency could be obtained by chirping applied laser pulses to elegantly compensate the frequency shift induced by intra-atomic collision. Our results could be useful for efficiently photoassociating ground-state molecules from a cold atomic gas with strong atom-atom collisional interaction.

Efficiency limitation for realizing an atom–molecule adiabatic transfer based on a chainwise system

“…Presently, we aim to extend our former results to a more generalized chainwise system and study its efficiency limit as more middle energy levels are included. In section II, we have developed a quasi-dark eigenstate approach and solved an adiabatic parameter r(t) to quantify the performance of the adiabatic passage [54]. If r(t) is small, the atom-molecule conversion can adiabatically follow the quasi-dark eigenstate and a high transfer efficiency will be achieved.…”