Realization of population inversion in a two-level system by damping field

We propose a new method for reversing the quantum state of a two-level system. From solving the time-dependent Schrödinger equation numerically, we show that by applying a classical decaying oscillatory field the state in a two-level system can be completely reversed if the parameters of the field satisfy certain conditions. The transition probability from one level to the other is calculated for different parameters and its maximum value can reach unity. By using such field with specific oscillatory frequency the Rabi oscillations between two levels in the case of applying a constant field can be suppressed and a stable manipulation of the quantum state can be performed. The estimation of such manipulation by using laser pulse acting on the states of hydrogen atom shows that the population inversion higher than 0.9 may be realized in less than 2 fs.