Nonlinear dynamics of ladder and lambda STIRAP

V. Dohm

Shao-Ying Meng, Libin Fu, Jie Liu

By generalizing the definition of fidelity for the nonlinear system, we investigate the dynamics and adiabaticity of the population transfer for atom-molecule three-level $\ensuremath{\Lambda}$ system on a stimulated Raman adiabatic passage (STIRAP). We find that the adiabatic fidelity for the coherent population trapping state or dark state, as the function of the adiabatic parameter, approaches to unit in a power law. The power exponent, however, is much less than the prediction of the linear adiabatic theorem. We further discuss how to achieve higher adiabatic fidelity for the dark state through optimizing the external parameters of the STIRAP.

M. Saadati-Niari, N. Shirkhanghah

We propose the use of the Stark-chirped rapid adiabatic passage (SCRAP) method to induce a complete population transfer in a nonlinear three-level Λ-type system (nl-SCRAP). We also use the nl-SCRAP method for creating stable diatomic ground molecular Bose–Einstein condensates (BECs) from atomic BECs. In this three-laser technique the pump and Stokes pulses are slightly detuned from transition frequencies, and a third strong hyperbolic-tangent laser pulse induces dynamic Stark shifts of the relevant transitions and compensates for third-order nonlinearities. If the timing of the three pulses is appropriately chosen, the nonlinear quantum system is prepared to almost complete population inversion between the two lower states in the Λ-like scheme. The paper shows that the efficiency of the nl-SCRAP is higher than the nonlinear stimulated Raman adiabatic passage (nl-STIRAP) technique, and this method can be used in one-photon as well as multi-photon transitions. The transfer process is robust concerning fluctuations of experimental parameters, such as peak Rabi frequencies, the time delay between pulses, and static detunings.

Joel Feldman, Horst Knörrer, Eugene Trubowitz B

Ying‐Yu Niu, Rong Wang

The population transfer of stimulated Raman adiabatic passage (STIRAP) is investigated using a time-dependent quantum wave packet method. The population is transferred from an initial state to a target state through the interaction of the external laser field with the permanent dipole moment and the transition dipole moment. The laser field is composed of an infrared pulse and a near ultraviolet pulse. The two pulses with small detunings are more efficient to achieve the STIRAP transition. The process of STIRAP is sensitive to the detunings of the two pulses. When the two detunings are the same in a Λ transition or the positive detuning of the pump pulse is equal to the negative detuning of the Stokes pulse in a ladder transition, the final population in the intermediate state can be eliminated and the target population is increased.

Yuan Sun, Harold J. Metcalf