Highly selective excitations of a three-level atomic system by zero- and nonzero-delayed lasers

Abstract

Highly selective excitations, which occur in a three-level system under the conditions of zero- and nonzero-delayed lasers, are examined. The detuning ranges which reach half inversion and their dependences on the laser conditions are obtained numerically using the Bloch equation. It is found that in the optimal detuning method which uses the zero-delayed lasers, the range is independent of the Rabi frequency and the detuning, but in the adiabatic passage which uses the nonzero-delayed lasers, the range is dependent on the Rabi frequency and the time delay. The inversion methods show strong dependences on the pulse length. It turns out that the optimal detuning method which has the narrow range is more appropriate to obtain highly selective excitation than the adiabatic passage. The mechanisms of population inversion and the decay effects between the methods are compared.