6533b7d3fe1ef96bd126079c

RESEARCH PRODUCT

Laser control of quantum systems by ultrafast parallel adiabatic passage : application to high fidelity population transfer, state selectivity, and superposition of states

subject

description

In this work we establish and test the technique of parallel adiabatic passage (PLAP) thatoptimizes the adiabatic passage in the sense that it selects specific paths that allow a fastadiabatic dynamics while preserving the standard robustness of adiabatic techniques. Theintuition of PLAP is based on the fact that the use of eigenvalues that are parallel for alltimes is expected to lead to a small nonadiabatic transition probability from Landau-Zeneranalysis for two-state approximations. In this work we test the robustness of this techniqueand show its superiority to the traditional linearly chirped dynamics with Gaussian pulses. Weshow its extension for two-photon and three-photon transitions on multilevel quantum systems,where the Stark shift plays an important role in a strong field regime. We have determined anoptimal pulse shaping in which the static and dynamic energy level shifts are simultaneouslycompensated by a programmed phase of a laser field. Next the local parallel adiabatic passagetechnique is presented. This corresponds to a dynamics where the eigenvalue of the populatedstate is parallel to the closest one at all times.We extend the idea of population transfer by adiabatic passage from the ground state toa superposition of states. The transfer is executed with spectrally shaped femtosecond laserpulses. The excited states are dynamically shifted in energy due to the presence of nonresonantcomponents of different channels. We show that this Stark shift can be compensated by anotherfield or by shaping appropriately the pulses.