Pulse-driven interwell carrier transfer in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>n</mml:mi></mml:math>-type doped asymmetric double quantum wells

Abstract

We use chirped pulses to achieve substantial electron population transfer from the wider well to the narrower well of an $n$-type doped asymmetric double quantum well (QW). To realize this goal we are guided by a generalization of the rotating-wave approximation to include, in the optical-Bloch equations for three-subband QW's, a time-varying central frequency equal to the renormalized intersubband transition energy. The energy-gap renormalization in our model is due to depolarization-shift effects. The first pulse central frequency is near the time-varying renormalized ${ϵ}_{2}\ensuremath{-}{ϵ}_{0}$ gap, while the second pulse is near the renormalized ${ϵ}_{2}\ensuremath{-}{ϵ}_{1}$ gap. An upper-bound estimate of the Hartree-Fock corrections to these transition energies is given. We find out that for the QW structure and the sheet density used these corrections are small.