Ultrafast edge photoexcitation and coherent oscillations in tunnel-coupled double quantum wells

Photoexcitation of electrons in double quantum wells is studied as a function of level splitting, duration of the light pulse ${\mathrm{\tau }}_{\mathit{p}}$, and light frequency. Dynamics of transitions between the upper states of the valence band and the tunnel-coupled pair of conduction band states is considered in the collisionless approximation. The nonmonotonic temporal dependence of the photoexcited electron concentration (the saturation value of this concentration determines the time-integrated interband photoluminescence intensity) is obtained for the times t∼${\mathrm{\tau }}_{\mathit{p}}$. Transition from the nonperiodic (at t∼${\mathrm{\tau }}_{\mathit{p}}$) to the periodic (at t≫${\mathrm{\tau }}_{\mathit{p}}$) behavior of the dipole moment oscillations is described.