Population transfer and pulse propagation in certain closed-loop systems

Michael Fleischhauer, Razmik G. Unanyan, Bruce W. Shore +1 more

We show that the physical mechanism of population transfer in a three-level system with a closed loop of coherent couplings is not equivalent to an adiabatic rotation of the dark state of the Hamiltonian, but corresponds to a rotation of a higher-order trapping state in a generalized adiabatic basis. The concept of generalized adiabatic basis sets is used as a constructive tool to design pulse sequences for stimulated Raman adiabatic passage, which also give maximum population transfer under conditions when the usual condition of adiabaticty is only poorly fulfilled. Under certain conditions for the pulses (generalized matched pulses), there exists a higher-order trapping state, which is an exact constant of motion, and analytic solutions for the atomic dynamics can be derived.

Mustafa Demirplak

Marius Romuald Kamsap, Maïk Delon Mboumba, M.E. Ateuafack +3 more

Abstract This study demonstrates complete adiabatic population transfer in a closed three-level atomic system using chirped laser pulses. By satisfying the three-photon resonance condition, we effectively mitigate the first-order Doppler effect. Under the assumption of weak coupling between the stable levels, we show that relative phase fluctuations of the lasers exert a negligible influence on the population dynamics during the transfer process. A comprehensive analysis of the system parameters is conducted to determine the optimal conditions for achieving 100% population transfer while minimizing the excited state population

Erwin Louis Hahn

Klaas Bergmann, J. Martin, Bruce W. Shore

Seyedeh Hamideh Kazemi, Mohammad Mahmoudi

We report a scheme to achieve coherent population transfer in a four-level double-Λ closed-loop atomic system by utilizing the coherent beams with Laguerre–Gaussian profiles. It is demonstrated that a maximal population transfer is achieved for a special value of the relative phase of the applied fields. We then compare the results with a similar configuration, but for the laser pulses with the usual Gaussian profiles and conclude that using the Laguerre–Gaussian modes can result in almost complete population transfer. Besides, the creation of a superposition between two lower states can be achieved through properly changing the relative phase. The suggested scheme may hold great practicality for the realization of the population transfer as well as creation of the superposition between states in the quantum systems with multiple states.