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 τp, 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∼τp. Transition from the nonperiodic (at t∼τp) to the periodic (at tτp) behavior of the dipole moment oscillations is described. © 1995 The American Physical Society.