Efficient population transfer by delayed pulses despite coupling ambiguity
Fachbereich Physik, Universität Kaiserslautern,
67653 Kaiserslautern, Germany
Revised: 15 July 1999
Published online: 13 August 2013
In traditional schemes of multilevel multilaser excitation, each laser pulse interacts with only one pair of states, and the rotating wave approximation (RWA) is applicable. Here we study the population transfer process in a three-state system when each of the two lasers interacts with each of the pair of states and when the Rabi frequencies characterizing the interaction strengths of the system are comparable to or larger than the difference of the transition frequencies. We show that complete and robust population transfer is possible under conditions more general than those hitherto considered necessary for stimulated Raman adiabatic passage (STIRAP) or for successive π pulses. Using adiabatic Floquet theory we show that successful population transfer can be interpreted as adiabatic passage by means of a transfer state which connects the initial and final states. The Floquet picture offers a convenient interpretation of the population transfer as accompanied by multiple absorption of photons from or emission into the laser fields.
PACS: 42.50.Hz – Strong-field excitation of optical transitions in quantum systems; multi-photon processes; dynamic Stark shift / 32.80.Wr – Other multiphoton processes / 32.80.Bx – Level crossing and optical pumping
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000