Excitation and control of level populations in rectangular quantum wells by unipolar half-cycle attosecond pulses

Abstract

Unipolar and quasi-unipolar half-cycle pulses represent the limit of the pulse shortening in a given spectral range. So far such pulses have become a subject of active research due to their potential in the ultrafast optics and study of new regimes of light–matter interactions with subcycle resolution. Here, we show the possibility of the effective ultrafast control of the level populations in 1D rectangular quantum wells (such a model is used for modeling semiconductor nanostructures and nanoparticles) by the half-cycle unipolar attosecond light pulses in comparison to the single-cycle ones. It is shown that the population dynamics is determined by the electric pulse area divided into its characteristic “scale,” which is given by the quantum well width when pulse duration is smaller than the orbital period of electrons in the ground state. Both the selective excitation of quantum states and the feasibility of the population inversion by subcycle unipolar pulses are demonstrated.